diff --git a/docs/api/stack-image-template.md b/docs/api/stack-image-template.md
new file mode 100644
index 000000000..fd2007b9b
--- /dev/null
+++ b/docs/api/stack-image-template.md
@@ -0,0 +1,42 @@
+# Stack image template
+
+Use `datamachine/render-image-template` with `template_id: "stack"`, or:
+
+```sh
+wp datamachine image render --template_id=stack --preset=print_pocket_flyer --data='{"background":"#182028","blocks":[{"type":"text","text":"Get involved","font":"heading","size":80,"fit":true},{"type":"qr","url":"https://example.org/join","size":0.45,"gap_before":24},{"type":"list","items":["Scan the code","Choose a project","Invite a friend"],"style":"numbered","size":36,"gap_before":24}]}'
+```
+
+All platform presets work. Pixel dimensions scale from a 1080px-wide base.
+Top-level fields are `background` (hex or brand color token, default
+`background_dark`), `padding` (64), `align` (`center` or `left`), and ordered
+`blocks`. Colors accept hex or brand color keys; fonts accept `heading`, `body`,
+`display`, or `brand`.
+
+Every block accepts `gap_before` in base pixels:
+
+| Type | Fields |
+| --- | --- |
+| `text` | `text`, `font`, `color`, `size` (32), `fit`, `max_size`, `wrap` (true), `line_height` (1.2), `align` |
+| `image` | `path` or `attachment_id`, `width` (fraction <=1 or base pixels), `max_height` |
+| `qr` | `url`, `size` (content-width fraction, default .5), `card_color` (white), `quiet_modules` (1–4) |
+| `row` | `items` (text/image blocks), `gap` (16 base pixels); one line, vertically centered |
+| `list` | string `items`, `style` (`numbered`, `bullets`, `plain`), `marker_color`, `font`, `color`, `size`, `line_height` |
+| `divider` | `width` (fraction or base pixels), `thickness` (2), `color` |
+| `spacer` | `height`, `flex` |
+
+`fit` text shrinks to fit its width; with wrapping enabled it fits the longest
+word, and with `wrap: false` it fits the entire line. `max_size` optionally
+sets a larger starting size. If the stack is too tall, fit-enabled text and
+lists shrink proportionally, down to 1px, before reporting overflow. Fixed
+images, QR codes, spacers and non-fitting text retain their dimensions. No
+blocks are removed to resolve overflow.
+
+Flex spacers share spare height; without flex spacers, spare height is spread
+between blocks. QR quiet-zone cards are included in layout bounds and use
+nearest-neighbor scaling. A QR provider must answer the existing
+`datamachine/image_generation/qr_image_path` filter; it receives the final QR
+pixel size and returns a temporary image that the template deletes.
+
+Ability results include `warnings` for unresolved overflow, unavailable assets
+and unsupported blocks. `dropped_fields` identifies skipped asset/block paths;
+height overflow itself does not mark blocks as dropped. The CLI prints warnings.
diff --git a/inc/Abilities/Media/ImageTemplateAbilities.php b/inc/Abilities/Media/ImageTemplateAbilities.php
index 8d550dcb6..68b7b1b4e 100644
--- a/inc/Abilities/Media/ImageTemplateAbilities.php
+++ b/inc/Abilities/Media/ImageTemplateAbilities.php
@@ -111,7 +111,7 @@ private static function render_image_template_definition(): array {
 					),
 					'data'        => array(
 						'type'        => 'object',
-						'description' => 'Structured data matching the template fields',
+						'description' => 'Structured data matching the template fields. stack accepts background (hex/token), padding (1080px base), align (center|left), blocks: ordered text (text/font/color/size/fit/max_size/wrap/line_height/align), image (path or attachment_id/width/max_height), qr (url/size/card_color/quiet_modules), row (text/image items, gap), list (items/style/marker_color/font/color/size), divider (width/thickness/color), spacer (height/flex). Every block accepts gap_before. Widths are fractions or base px; QR size is a fraction.',
 					),
 					'brand'       => BrandTokens::override_schema(),
 					'preset'      => array(
@@ -177,6 +177,11 @@ private static function render_image_template_definition(): array {
 						'items'       => array( 'type' => 'string' ),
 						'description' => 'Field keys the template omitted to make the layout fit. Empty when every field was drawn.',
 					),
+					'warnings'       => array(
+						'type'        => 'array',
+						'items'       => array( 'type' => 'string' ),
+						'description' => 'Layout and asset warnings, including unresolved stack overflow. No blocks are removed to fit a stack.',
+					),
 					'message'        => array( 'type' => 'string' ),
 				),
 			),
@@ -308,6 +313,10 @@ public static function renderTemplate( array $input ): array|\WP_Error {
 			? array_values( array_map( 'strval', (array) $template->get_dropped_fields() ) )
 			: array();
 
+		$warnings = method_exists( $template, 'get_warnings' )
+			? array_values( array_map( 'strval', (array) $template->get_warnings() ) )
+			: array();
+
 		// Keep local paths intact for in-process callers; publish temp renders
 		// through the existing repository for remote callers.
 		if ( 'cached_file' !== $output ) {
@@ -336,6 +345,7 @@ public static function renderTemplate( array $input ): array|\WP_Error {
 				'file_urls'      => $file_urls,
 				'template_id'    => $template_id,
 				'dropped_fields' => $dropped_fields,
+				'warnings'       => $warnings,
 				'message'        => sprintf( 'Generated %d image(s) using template "%s"', count( $file_paths ), $template_id ),
 			);
 		}
@@ -352,6 +362,7 @@ public static function renderTemplate( array $input ): array|\WP_Error {
 				'success'        => true,
 				'template_id'    => $template_id,
 				'dropped_fields' => $dropped_fields,
+				'warnings'       => $warnings,
 			),
 			$cached_result
 		);
diff --git a/inc/Abilities/Media/Templates/PosterTemplate.php b/inc/Abilities/Media/Templates/PosterTemplate.php
index 6dedb71f7..0aa94d37e 100644
--- a/inc/Abilities/Media/Templates/PosterTemplate.php
+++ b/inc/Abilities/Media/Templates/PosterTemplate.php
@@ -1593,18 +1593,7 @@ private static function widest_line_width( GDRenderer $r, string $text, int $siz
 	 * @param int        $w    Column width.
 	 */
 	private static function fit_word_size( GDRenderer $r, string $text, int $size, string $font, int $w ): int {
-		$words = preg_split( '/\s+/', trim( $text ) );
-		while ( $size > 12 ) {
-			$widest = 0;
-			foreach ( (array) $words as $word ) {
-				$widest = max( $widest, $r->measure_text_width( (string) $word, $size, $font ) );
-			}
-			if ( $widest <= $w ) {
-				break;
-			}
-			--$size;
-		}
-		return $size;
+		return TemplateHelpers::fit_text( $r, $text, $size, $font, $w, true, 12 );
 	}
 
 	/**
@@ -1994,19 +1983,6 @@ public static function plan_layout( int $height, int $margin, int $content_heigh
 	 * @return string|null Readable temp PNG path the caller deletes, or null.
 	 */
 	private static function qr_image_path( string $url, int $size ): ?string {
-		if ( '' === $url ) {
-			return null;
-		}
-		/**
-		 * Resolve a QR code image for a poster.
-		 *
-		 * @param string|null $path Null by default (no QR provider).
-		 * @param string      $url  URL to encode.
-		 * @param int         $size Drawn size in pixels.
-		 * @return string|null Path to a temp PNG the template owns and deletes.
-		 */
-		// phpcs:ignore WordPress.NamingConventions.ValidHookName -- Intentional slash-separated hook namespace.
-		$path = apply_filters( 'datamachine/image_generation/qr_image_path', null, $url, $size );
-		return ( is_string( $path ) && '' !== $path && is_readable( $path ) ) ? $path : null;
+		return TemplateHelpers::qr_image_path( $url, $size );
 	}
 }
diff --git a/inc/Abilities/Media/Templates/StackTemplate.php b/inc/Abilities/Media/Templates/StackTemplate.php
new file mode 100644
index 000000000..895ff121b
--- /dev/null
+++ b/inc/Abilities/Media/Templates/StackTemplate.php
@@ -0,0 +1,320 @@
+<?php
+/**
+ * Composable top-to-bottom image layout. All pixel values use a 1080px base
+ * width and scale with the selected preset. Colors accept BrandTokens keys or
+ * hex; fonts accept heading, body, display or brand token keys.
+ *
+ * Fields: background (default background_dark), padding (default 64), align
+ * (center|left), blocks (ordered array). Every block accepts gap_before (px).
+ * Block schema:
+ * - text: text, font, color, size (32), fit (false), max_size, wrap (true),
+ *   line_height (1.2), align. Fit shrinks words for wrapped text, or the entire
+ *   line when wrap=false; max_size optionally supplies a larger starting size.
+ * - image: path or attachment_id, width (fraction <=1 or base px), max_height.
+ * - qr: url, size (content-width fraction, default .5), card_color (white),
+ *   quiet_modules (1..4, default 4). Provider receives final QR pixel size.
+ * - row: items (text/image blocks), gap (16px); centered vertically, one line.
+ * - list: items (strings), style (numbered|bullets|plain), marker_color,
+ *   font, color, size (32), line_height (1.2).
+ * - divider: width (fraction or px), thickness (2), color.
+ * - spacer: height (px), flex (false). Flex spacers receive spare height;
+ *   otherwise spare height is distributed between blocks.
+ *
+ * Overflow shrinks fit text and lists proportionally to a minimum of 1px.
+ * Blocks are never removed to fit. Warnings describe unresolved overflow,
+ * invalid blocks and unavailable assets; skipped field paths are also exposed
+ * through get_dropped_fields(), the existing ability reporting mechanism.
+ *
+ * @package DataMachine\Abilities\Media
+ */
+namespace DataMachine\Abilities\Media\Templates;
+
+use DataMachine\Abilities\Media\BrandTokens;
+use DataMachine\Abilities\Media\GDRenderer;
+use DataMachine\Abilities\Media\TemplateInterface;
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+class StackTemplate implements TemplateInterface {
+	private array $warnings = array();
+	private array $dropped  = array();
+	private array $tokens   = array();
+
+	public function get_id(): string {
+		return 'stack';
+	}
+	public function get_name(): string {
+		return 'Stack';
+	}
+	public function get_description(): string {
+		return 'An ordered vertical stack of text, images, QR codes, rows, lists, dividers and spacers.';
+	}
+	public function get_default_preset(): string {
+		return 'instagram_feed_portrait';
+	}
+	public function get_warnings(): array {
+		return $this->warnings;
+	}
+	public function get_dropped_fields(): array {
+		return array_values( $this->dropped );
+	}
+
+	public function get_fields(): array {
+		return array(
+			'background' => array(
+				'label'    => 'Background hex or brand color token (default background_dark)',
+				'type'     => 'string',
+				'required' => false,
+			),
+			'padding'    => array(
+				'label'    => 'Padding in pixels at 1080px base width (default 64)',
+				'type'     => 'number',
+				'required' => false,
+			),
+			'align'      => array(
+				'label'    => 'Default alignment: center or left',
+				'type'     => 'string',
+				'required' => false,
+			),
+			'blocks'     => array(
+				'label'    => 'Ordered blocks; each accepts gap_before (base px). text: text/font/color/size/fit/max_size/wrap/line_height/align; image: path or attachment_id, width (fraction or px), max_height; qr: url/size (fraction)/card_color/quiet_modules; row: items (text/image), gap; list: items/style (numbered|bullets|plain)/marker_color/font/color/size; divider: width/thickness/color; spacer: height/flex. Pixels scale from 1080px. Fonts and colors accept brand tokens; colors also accept hex.',
+				'type'     => 'array',
+				'required' => true,
+			),
+		);
+	}
+
+	private function warn( string $key, string $message, bool $skip = true ): void {
+		$this->warnings[ $key ] = $message;
+		if ( $skip ) {
+			$this->dropped[ $key ] = $key;
+		}
+	}
+
+	private function color( GDRenderer $r, string $value ): int {
+		$hex = $this->tokens['colors'][ $value ] ?? $value;
+		if ( ! preg_match( '/^#?[a-f0-9]{3}(?:[a-f0-9]{3})?$/i', $hex ) ) {
+			$hex = '#ffffff';
+		}
+		$hex = ltrim( $hex, '#' );
+		if ( 3 === strlen( $hex ) ) {
+			$hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
+		}
+		return $r->color_hex( $hex, $hex );
+	}
+
+	private function extent( float $value, int $width, float $scale ): int {
+		return max( 1, min( $width, (int) round( $value <= 1 ? $value * $width : $value * $scale ) ) );
+	}
+
+	/** Measure without drawing or requesting QR files. Returned boxes are also used to draw. */
+	private function measure( GDRenderer $r, array $b, int $width, float $scale, float $shrink, string $key, string $align ): array {
+		$type = $b['type'] ?? '';
+		$p    = array(
+			'type'   => $type,
+			'width'  => $width,
+			'height' => 0,
+			'gap'    => max( 0, (int) round( (float) ( $b['gap_before'] ?? 0 ) * $scale ) ),
+			'align'  => $b['align'] ?? $align,
+			'key'    => $key,
+		);
+		if ( 'text' === $type || 'list' === $type ) {
+			$p['font']        = in_array( $b['font'] ?? 'body', array( 'heading', 'body', 'display', 'brand' ), true ) ? ( $b['font'] ?? 'body' ) : 'body';
+			$p['size']        = max( 1, (int) round( (float) ( ! empty( $b['fit'] ) ? ( $b['max_size'] ?? $b['size'] ?? 32 ) : ( $b['size'] ?? 32 ) ) * $scale * ( 'list' === $type || ! empty( $b['fit'] ) ? $shrink : 1 ) ) );
+			$p['line_height'] = max( 1, (float) ( $b['line_height'] ?? 1.2 ) );
+			$p['color']       = $b['color'] ?? 'text_inverse';
+			$p['wrap']        = $b['wrap'] ?? true;
+			$p['text']        = (string) ( $b['text'] ?? '' );
+			if ( 'text' === $type ) {
+				if ( ! empty( $b['fit'] ) ) {
+					$p['size'] = TemplateHelpers::fit_text( $r, $p['text'], $p['size'], $p['font'], $width, (bool) $p['wrap'] );
+				}
+				$p['height'] = $p['wrap'] ? $r->measure_text_height( $p['text'], $p['size'], $p['font'], $width, $p['line_height'] ) : (int) ceil( $p['size'] * $p['line_height'] );
+			} else {
+				$p['style']        = $b['style'] ?? 'numbered';
+				$p['marker_color'] = $b['marker_color'] ?? 'accent';
+				$p['items']        = array_values( array_filter( (array) ( $b['items'] ?? array() ), 'is_scalar' ) );
+				$p['gutter']       = 'plain' === $p['style'] ? 0 : $r->measure_text_width( (string) count( $p['items'] ) . '.', $p['size'], $p['font'] ) + (int) ceil( $p['size'] * .6 );
+				foreach ( $p['items'] as $item ) {
+					$p['height'] += $r->measure_text_height( (string) $item, $p['size'], $p['font'], max( 1, $width - $p['gutter'] ), $p['line_height'] );
+				}
+			}
+		} elseif ( 'image' === $type ) {
+			$path = $b['path'] ?? $b['attachment_id'] ?? '';
+			if ( is_numeric( $path ) ) {
+				$path = get_attached_file( (int) $path );
+			}
+			$info = is_string( $path ) && is_readable( $path ) ? getimagesize( $path ) : false;
+			if ( ! $info || ! in_array( $info[2], array( IMAGETYPE_PNG, IMAGETYPE_JPEG, IMAGETYPE_WEBP ), true ) ) {
+				$p['width'] = 0;
+				$this->warn( $key, "$key: unreadable or unsupported image skipped." );
+			} else {
+				$p['path']   = $path;
+				$p['width']  = $this->extent( (float) ( $b['width'] ?? 1 ), $width, $scale );
+				$p['height'] = max( 1, (int) round( $p['width'] * $info[1] / $info[0] ) );
+				$ratio       = min( 1, max( 1, (float) ( $b['max_height'] ?? $p['height'] / $scale ) * $scale ) / $p['height'] );
+				$p['width']  = max( 1, (int) round( $p['width'] * $ratio ) );
+				$p['height'] = max( 1, (int) round( $p['height'] * $ratio ) );
+			}
+		} elseif ( 'qr' === $type ) {
+			$p['size'] = $this->extent( min( 1, max( .01, (float) ( $b['size'] ?? .5 ) ) ), $width, $scale );
+			$p['pad']  = (int) ceil( $p['size'] * max( 1, min( 4, (int) ( $b['quiet_modules'] ?? 4 ) ) ) / 33 );
+			// Keep the quiet-zone card inside the content area even at size=1.
+			while ( $p['size'] > 1 && $p['size'] + 2 * $p['pad'] > $width ) {
+				--$p['size'];
+				$p['pad'] = (int) ceil( $p['size'] * max( 1, min( 4, (int) ( $b['quiet_modules'] ?? 4 ) ) ) / 33 );
+			}
+			$p['width']  = $p['size'] + 2 * $p['pad'];
+			$p['height'] = $p['width'];
+			$p['url']    = (string) ( $b['url'] ?? '' );
+			$p['color']  = $b['card_color'] ?? '#ffffff';
+		} elseif ( 'row' === $type ) {
+			$p['children'] = array();
+			$p['row_gap']  = max( 0, (int) round( (float) ( $b['gap'] ?? 16 ) * $scale ) );
+			$used          = 0;
+			foreach ( (array) ( $b['items'] ?? array() ) as $i => $item ) {
+				if ( ! is_array( $item ) || ! in_array( $item['type'] ?? '', array( 'text', 'image' ), true ) ) {
+					$this->warn( "$key.items.$i", "$key.items.$i: row only supports text and image." );
+					continue;
+				}
+				$item['wrap'] = false;
+				$child        = $this->measure( $r, $item, $width, $scale, $shrink, "$key.items.$i", 'left' );
+				if ( 'text' === $child['type'] ) {
+					$child['width'] = $r->measure_text_width( $child['text'], $child['size'], $child['font'] );
+				}
+				$child['x']      = $used;
+				$used           += $child['width'] + $p['row_gap'];
+				$p['height']     = max( $p['height'], $child['height'] );
+				$p['children'][] = $child;
+			}
+			$p['width'] = max( 0, $used - $p['row_gap'] );
+			if ( $p['width'] > $width ) {
+				$this->warn( $key, "$key: row exceeds content width.", false );
+			}
+		} elseif ( 'divider' === $type ) {
+			$p['width']  = $this->extent( (float) ( $b['width'] ?? 1 ), $width, $scale );
+			$p['height'] = max( 1, (int) round( (float) ( $b['thickness'] ?? 2 ) * $scale ) );
+			$p['color']  = $b['color'] ?? 'accent';
+		} elseif ( 'spacer' === $type ) {
+			$p['height'] = max( 0, (int) round( (float) ( $b['height'] ?? 0 ) * $scale ) );
+			$p['flex']   = ! empty( $b['flex'] );
+		} else {
+			$this->warn( $key, "$key: unknown block type skipped." );
+		}
+		return $p;
+	}
+
+	/** Public measured layout for inspection; no assets are generated here. */
+	public function plan_layout( GDRenderer $r, array $data ): array {
+		$this->warnings = array();
+		$this->dropped  = array();
+		$this->tokens   = BrandTokens::get( 'stack', $data );
+		foreach ( array( 'heading', 'body', 'display', 'brand' ) as $font ) {
+			$r->register_font( $font, (string) ( $this->tokens['fonts'][ $font ] ?? $this->tokens['fonts']['body'] ?? '' ) );
+		}
+		$scale     = $r->get_width() / 1080;
+		$padding   = max( 0, min( (int) round( (float) ( $data['padding'] ?? 64 ) * $scale ), (int) floor( min( $r->get_width(), $r->get_height() ) / 2 ) - 1 ) );
+		$width     = max( 1, $r->get_width() - 2 * $padding );
+		$available = $r->get_height() - 2 * $padding;
+		$shrink    = 1;
+		for ( $pass = 0; $pass < 80; ++$pass ) {
+			// Rebuild diagnostics too: a row may stop overflowing after fitting.
+			$this->warnings = array();
+			$this->dropped  = array();
+			$boxes          = array();
+			$total          = 0;
+			foreach ( (array) ( $data['blocks'] ?? array() ) as $i => $block ) {
+				if ( ! is_array( $block ) ) {
+					$this->warn( "blocks.$i", "blocks.$i: invalid block skipped." );
+					continue;
+				}
+				$box     = $this->measure( $r, $block, $width, $scale, $shrink, "blocks.$i", $data['align'] ?? 'center' );
+				$total  += $box['gap'] + $box['height'];
+				$boxes[] = $box;
+			}
+			if ( $total <= $available || $shrink <= .001 ) {
+				break;
+			}
+			$shrink *= max( .1, min( .9, $available / max( 1, $total ) ) );
+		}
+		if ( $total > $available ) {
+			$this->warn( 'overflow', 'Stack content exceeds canvas height after fitting; no blocks were dropped.', false );
+		}
+		$flex    = count( array_filter( $boxes, static fn( $b ) => ! empty( $b['flex'] ) ) );
+		$spare   = max( 0, $available - $total );
+		$between = ! $flex && count( $boxes ) > 1 ? $spare / ( count( $boxes ) - 1 ) : 0;
+		$y       = $padding;
+		foreach ( $boxes as &$box ) {
+			$y       += $box['gap'];
+			$box['x'] = $padding + ( 'left' === $box['align'] ? 0 : (int) round( ( $width - $box['width'] ) / 2 ) );
+			$box['y'] = (int) round( $y );
+			if ( ! empty( $box['flex'] ) ) {
+				$box['height'] += (int) floor( $spare / $flex );
+			}
+			$y += $box['height'] + $between;
+		}
+		unset( $box );
+		return $boxes;
+	}
+
+	private function draw( GDRenderer $r, array $b, int $x, int $y ): void {
+		if ( 'text' === $b['type'] ) {
+			$color = $this->color( $r, $b['color'] );
+			if ( $b['wrap'] ) {
+				$r->draw_text_wrapped( $b['text'], $b['size'], $x, $y, $color, $b['font'], $b['width'], $b['line_height'], $b['align'] );
+			} else {
+				$offset = 'left' === $b['align'] ? 0 : (int) round( ( $b['width'] - $r->measure_text_width( $b['text'], $b['size'], $b['font'] ) ) / 2 );
+				$r->draw_text( $b['text'], $b['size'], $x + $offset, $y + $b['size'], $color, $b['font'] );
+			}
+		} elseif ( 'image' === $b['type'] && isset( $b['path'] ) ) {
+			$r->overlay_image( $b['path'], $x, $y, $b['width'], $b['height'] );
+		} elseif ( 'qr' === $b['type'] ) {
+			$path = TemplateHelpers::qr_image_path( $b['url'], $b['size'] );
+			if ( ! $path ) {
+				$this->warn( $b['key'], $b['key'] . ': QR provider unavailable.' );
+				return;
+			}
+			try {
+				$r->filled_rect( $x, $y, $x + $b['width'] - 1, $y + $b['height'] - 1, $this->color( $r, $b['color'] ) );
+				$r->overlay_image( $path, $x + $b['pad'], $y + $b['pad'], $b['size'], $b['size'], 100, false );
+			} finally {
+				wp_delete_file( $path );
+			}
+		} elseif ( 'row' === $b['type'] ) {
+			foreach ( $b['children'] as $child ) {
+				$this->draw( $r, $child, $x + $child['x'], $y + (int) round( ( $b['height'] - $child['height'] ) / 2 ) );
+			}
+		} elseif ( 'list' === $b['type'] ) {
+			foreach ( $b['items'] as $i => $item ) {
+				$marker = 'numbered' === $b['style'] ? ( $i + 1 ) . '.' : ( 'bullets' === $b['style'] ? '•' : '' );
+				if ( '' !== $marker ) {
+					$r->draw_text( $marker, $b['size'], $x, $y + $b['size'], $this->color( $r, $b['marker_color'] ), $b['font'] );
+				}
+				$y = $r->draw_text_wrapped( (string) $item, $b['size'], $x + $b['gutter'], $y, $this->color( $r, $b['color'] ), $b['font'], max( 1, (int) ( $b['width'] - $b['gutter'] ) ), $b['line_height'] );
+			}
+		} elseif ( 'divider' === $b['type'] ) {
+			$r->filled_rect( $x, $y, $x + $b['width'] - 1, $y + $b['height'] - 1, $this->color( $r, $b['color'] ) );
+		}
+	}
+
+	public function render( array $data, GDRenderer $renderer, array $options = array() ): array {
+		$renderer->create_canvas( (string) ( $options['preset'] ?? $this->get_default_preset() ) );
+		if ( ! $renderer->get_image() ) {
+			return array();
+		}
+		$boxes = $this->plan_layout( $renderer, $data );
+		$renderer->fill( $this->color( $renderer, $data['background'] ?? 'background_dark' ) );
+		foreach ( $boxes as $box ) {
+			$this->draw( $renderer, $box, $box['x'], $box['y'] );
+		}
+		$format   = (string) ( $options['format'] ?? 'png' );
+		$context  = (array) ( $options['context'] ?? array() );
+		$filename = (string) ( $options['filename'] ?? 'stack.' . ( 'jpeg' === $format ? 'jpg' : 'png' ) );
+		$path     = ! empty( $context['pipeline_id'] ) && ! empty( $context['flow_id'] )
+			? $renderer->save_to_repository( $filename, $context, $format )
+			: $renderer->save_temp( $format );
+		return $path ? array( $path ) : array();
+	}
+}
diff --git a/inc/Abilities/Media/Templates/TemplateHelpers.php b/inc/Abilities/Media/Templates/TemplateHelpers.php
new file mode 100644
index 000000000..1375720e5
--- /dev/null
+++ b/inc/Abilities/Media/Templates/TemplateHelpers.php
@@ -0,0 +1,41 @@
+<?php
+/**
+ * Small shared image-template primitives.
+ *
+ * @package DataMachine\Abilities\Media
+ */
+namespace DataMachine\Abilities\Media\Templates;
+
+use DataMachine\Abilities\Media\GDRenderer;
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+final class TemplateHelpers {
+	/** Resolve a provider-owned temporary QR file; caller deletes it after drawing. */
+	public static function qr_image_path( string $url, int $size ): ?string {
+		if ( '' === $url ) {
+			return null;
+		}
+		// phpcs:ignore WordPress.NamingConventions.ValidHookName
+		$path = apply_filters( 'datamachine/image_generation/qr_image_path', null, $url, $size );
+		return is_string( $path ) && is_readable( $path ) ? $path : null;
+	}
+
+	/** Shrink until every word (or the whole unwrapped line) fits the width. */
+	public static function fit_text( GDRenderer $r, string $text, int $size, string $font, int $width, bool $wrap = true, int $minimum = 1 ): int {
+		$parts = $wrap ? preg_split( '/\s+/', trim( $text ) ) : array( $text );
+		while ( $size > $minimum ) {
+			$widest = 0;
+			foreach ( (array) $parts as $part ) {
+				$widest = max( $widest, $r->measure_text_width( (string) $part, $size, $font ) );
+			}
+			if ( $widest <= $width ) {
+				break;
+			}
+			--$size;
+		}
+		return $size;
+	}
+}
diff --git a/inc/Cli/Commands/ImageCommand.php b/inc/Cli/Commands/ImageCommand.php
index 78ea39df6..482f5e216 100644
--- a/inc/Cli/Commands/ImageCommand.php
+++ b/inc/Cli/Commands/ImageCommand.php
@@ -261,6 +261,10 @@ public function render( array $args, array $assoc_args ): void {
 
 		WP_CLI::success( $result['message'] ?? 'Template rendered.' );
 
+		foreach ( $result['warnings'] ?? array() as $warning ) {
+			WP_CLI::warning( $warning );
+		}
+
 		$dropped_fields = $result['dropped_fields'] ?? array();
 		if ( ! empty( $dropped_fields ) ) {
 			WP_CLI::warning( sprintf( 'Dropped fields to fit the layout: %s', implode( ', ', $dropped_fields ) ) );
diff --git a/inc/Core/Bootstrap/HostIntegrationServiceProvider.php b/inc/Core/Bootstrap/HostIntegrationServiceProvider.php
index 3e75a71f8..174c99166 100644
--- a/inc/Core/Bootstrap/HostIntegrationServiceProvider.php
+++ b/inc/Core/Bootstrap/HostIntegrationServiceProvider.php
@@ -149,6 +149,7 @@ public static function pending_action_permission(): bool {
 	public static function register_image_templates( array $templates ): array {
 		$templates['flow_diagram'] ??= \DataMachine\Abilities\Media\Templates\FlowDiagramTemplate::class;
 		$templates['poster']       ??= \DataMachine\Abilities\Media\Templates\PosterTemplate::class;
+		$templates['stack']        ??= \DataMachine\Abilities\Media\Templates\StackTemplate::class;
 		return $templates;
 	}
 
diff --git a/tests/Unit/Abilities/Media/StackTemplateTest.php b/tests/Unit/Abilities/Media/StackTemplateTest.php
new file mode 100644
index 000000000..49367f514
--- /dev/null
+++ b/tests/Unit/Abilities/Media/StackTemplateTest.php
@@ -0,0 +1,313 @@
+<?php
+/**
+ * Pixel renders and measured layout coverage for the generic stack template.
+ *
+ * @package DataMachine\Tests
+ */
+namespace {
+	if ( ! defined( 'ABSPATH' ) ) {
+		define( 'ABSPATH', '/tmp/' ); }
+	if ( ! function_exists( 'apply_filters' ) ) {
+		function apply_filters( $tag, $value, ...$args ) {
+			if ( 'datamachine/image_generation/qr_image_path' === $tag && isset( $GLOBALS['dm_stack_qr'] ) ) {
+				return ( $GLOBALS['dm_stack_qr'] )( $value, ...$args );
+			}
+			return $value;
+		}
+	}
+	if ( ! function_exists( 'do_action' ) ) {
+		function do_action( ...$args ) {}
+	}
+	if ( ! function_exists( 'get_option' ) ) {
+		function get_option( $name, $default = false ) {
+			return $default; }
+	}
+	if ( ! function_exists( 'get_template_directory' ) ) {
+		function get_template_directory() {
+			return '/tmp/no-theme'; }
+	}
+	if ( ! function_exists( 'wp_delete_file' ) ) {
+		function wp_delete_file( $path ) {
+			if ( is_file( $path ) ) {
+				unlink( $path ); } }
+	}
+}
+
+namespace DataMachine\Tests\Unit\Abilities\Media {
+	use DataMachine\Abilities\Media\GDRenderer;
+	use DataMachine\Abilities\Media\PlatformPresets;
+	use DataMachine\Abilities\Media\Templates\StackTemplate;
+	use PHPUnit\Framework\TestCase;
+
+	class StackTemplateTest extends TestCase {
+		private array $files = array();
+		private $provider;
+
+		protected function setUp(): void {
+			if ( ! extension_loaded( 'gd' ) ) {
+				$this->markTestSkipped( 'GD required.' ); }
+			$this->provider = static function ( $path, $url, $size ) {
+				return isset( $GLOBALS['dm_stack_qr'] ) ? ( $GLOBALS['dm_stack_qr'] )( $path, $url, $size ) : $path;
+			};
+			if ( function_exists( 'add_filter' ) ) {
+				add_filter( 'datamachine/image_generation/qr_image_path', $this->provider, 10, 3 );
+			}
+		}
+
+		protected function tearDown(): void {
+			unset( $GLOBALS['dm_stack_qr'] );
+			if ( function_exists( 'remove_filter' ) ) {
+				remove_filter( 'datamachine/image_generation/qr_image_path', $this->provider, 10 );
+			}
+			foreach ( $this->files as $path ) {
+				if ( is_file( $path ) ) {
+					unlink( $path ); }
+			}
+		}
+
+		private function image(): string {
+			$path  = tempnam( sys_get_temp_dir(), 'stack-test-' );
+			$image = imagecreatetruecolor( 120, 40 );
+			imagefill( $image, 0, 0, imagecolorallocate( $image, 180, 20, 30 ) );
+			imagepng( $image, $path );
+			imagedestroy( $image );
+			$this->files[] = $path;
+			return $path;
+		}
+
+		public function test_core_registration_and_field_definitions(): void {
+			$templates = \DataMachine\Core\Bootstrap\HostIntegrationServiceProvider::register_image_templates( array() );
+			$this->assertSame( StackTemplate::class, $templates['stack'] );
+			$override = \DataMachine\Core\Bootstrap\HostIntegrationServiceProvider::register_image_templates( array( 'stack' => 'CustomTemplate' ) );
+			$this->assertSame( 'CustomTemplate', $override['stack'] );
+			$this->assertTrue( ( new StackTemplate() )->get_fields()['blocks']['required'] );
+		}
+
+		public function test_order_and_fit_width(): void {
+			$r     = ( new GDRenderer() )->create_canvas( 1080, 1350 );
+			$t     = new StackTemplate();
+			$boxes = $t->plan_layout(
+				$r,
+				array(
+					'blocks' => array(
+						array(
+							'type' => 'text',
+							'text' => 'A headline far too wide at its original size',
+							'size' => 250,
+							'fit'  => true,
+							'wrap' => false,
+						),
+						array(
+							'type'       => 'divider',
+							'gap_before' => 20,
+						),
+						array(
+							'type' => 'text',
+							'text' => 'Footer',
+						),
+					),
+				)
+			);
+			$this->assertLessThan( $boxes[1]['y'], $boxes[0]['y'] );
+			$this->assertLessThan( $boxes[2]['y'], $boxes[1]['y'] );
+			$this->assertLessThanOrEqual( $boxes[0]['width'], $r->measure_text_width( $boxes[0]['text'], $boxes[0]['size'], $boxes[0]['font'] ) );
+			$this->assertSame( array(), $t->get_warnings() );
+		}
+
+		public function test_overflow_shrinks_text_and_lists_before_warning(): void {
+			$r     = ( new GDRenderer() )->create_canvas( 1080, 600 );
+			$t     = new StackTemplate();
+			$data  = array(
+				'blocks' => array(
+					array(
+						'type' => 'text',
+						'text' => 'Headline',
+						'size' => 180,
+						'fit'  => true,
+					),
+					array(
+						'type'  => 'list',
+						'items' => array_fill( 0, 8, 'Read this step' ),
+						'size'  => 90,
+					),
+				),
+			);
+			$boxes = $t->plan_layout( $r, $data );
+			$this->assertLessThan( 180, $boxes[0]['size'] );
+			$this->assertLessThan( 90, $boxes[1]['size'] );
+			$this->assertSame( array(), $t->get_warnings() );
+			$this->assertLessThanOrEqual( 536, $boxes[1]['y'] + $boxes[1]['height'] );
+			$data['blocks'][] = array(
+				'type'   => 'spacer',
+				'height' => 1000,
+			);
+			$boxes            = $t->plan_layout( $r, $data );
+			$this->assertCount( 3, $boxes );
+			$this->assertSame( 1, $boxes[0]['size'] );
+			$this->assertSame( 1, $boxes[1]['size'] );
+			$this->assertArrayHasKey( 'overflow', $t->get_warnings() );
+			$this->assertSame( array(), $t->get_dropped_fields() );
+		}
+
+		public function test_missing_image_is_reported(): void {
+			$t     = new StackTemplate();
+			$boxes = $t->plan_layout(
+				( new GDRenderer() )->create_canvas( 1080, 1350 ),
+				array(
+					'blocks' => array(
+						array(
+							'type' => 'image',
+							'path' => '/missing/asset.png',
+						),
+					),
+				)
+			);
+			$this->assertSame( 0, $boxes[0]['height'] );
+			$this->assertSame( array( 'blocks.0' ), $t->get_dropped_fields() );
+			$this->assertStringContainsString( 'unreadable', $t->get_warnings()['blocks.0'] );
+		}
+
+		public function test_flex_spacer_and_row_centering(): void {
+			$t     = new StackTemplate();
+			$r     = ( new GDRenderer() )->create_canvas( 1080, 1350 );
+			$boxes = $t->plan_layout(
+				$r,
+				array(
+					'align'  => 'left',
+					'blocks' => array(
+						array(
+							'type'  => 'row',
+							'items' => array(
+								array(
+									'type' => 'text',
+									'text' => 'Presented by',
+								),
+								array(
+									'type'  => 'image',
+									'path'  => $this->image(),
+									'width' => 120,
+								),
+							),
+						),
+						array(
+							'type' => 'spacer',
+							'flex' => true,
+						),
+						array( 'type' => 'divider' ),
+					),
+				)
+			);
+			$this->assertGreaterThan( 1000, $boxes[1]['height'] );
+			$this->assertSame( 64, $boxes[0]['x'] );
+			$this->assertSame( 1286, $boxes[2]['y'] + $boxes[2]['height'] );
+			$this->assertCount( 2, $boxes[0]['children'] );
+		}
+
+		public function test_all_presets_render_and_missing_qr_warns(): void {
+			foreach ( PlatformPresets::names() as $preset ) {
+				$t = new StackTemplate();
+				$r = new GDRenderer();
+				$paths = $t->render( array( 'background' => '#123', 'blocks' => array( array( 'type' => 'text', 'text' => 'Hello', 'fit' => true ) ) ), $r, array( 'preset' => $preset ) );
+				$this->files = array_merge( $this->files, $paths );
+				$this->assertCount( 1, $paths, $preset );
+				$pixel = imagecolorat( $r->get_image(), 0, 0 );
+				$this->assertSame( 0x112233, $pixel & 0xffffff );
+			}
+			$t = new StackTemplate();
+			$GLOBALS['dm_stack_qr'] = static fn() => null;
+			$paths = $t->render( array( 'blocks' => array( array( 'type' => 'qr', 'url' => 'https://example.org', 'size' => 1 ) ) ), new GDRenderer() );
+			$this->files = array_merge( $this->files, $paths );
+			$this->assertSame( array( 'blocks.0' ), $t->get_dropped_fields() );
+			$this->assertStringContainsString( 'QR provider unavailable', $t->get_warnings()['blocks.0'] );
+		}
+
+		public function test_qr_card_stays_inside_content_width(): void {
+			$t = new StackTemplate();
+			$boxes = $t->plan_layout( ( new GDRenderer() )->create_canvas( 1080, 1350 ), array( 'blocks' => array( array( 'type' => 'qr', 'size' => 1, 'url' => 'https://example.org' ) ) ) );
+			$this->assertLessThanOrEqual( 952, $boxes[0]['width'] );
+			$this->assertGreaterThanOrEqual( 64, $boxes[0]['x'] );
+		}
+
+		public function test_representative_eight_block_render_on_print_and_feed(): void {
+			$requested              = array();
+			$GLOBALS['dm_stack_qr'] = function ( $path, $url, $size ) use ( &$requested ) {
+				$requested[] = $size;
+				return $this->image();
+			};
+			$data                   = array(
+				'blocks' => array(
+					array(
+						'type' => 'text',
+						'text' => 'Join the community',
+						'font' => 'heading',
+						'size' => 64,
+						'fit'  => true,
+					),
+					array(
+						'type' => 'text',
+						'text' => 'Scan to get started',
+						'size' => 30,
+					),
+					array(
+						'type' => 'qr',
+						'url'  => 'https://example.org/join',
+						'size' => .4,
+					),
+					array(
+						'type'       => 'image',
+						'path'       => $this->image(),
+						'width'      => .6,
+						'max_height' => 120,
+					),
+					array(
+						'type' => 'text',
+						'text' => 'A shared project',
+						'size' => 48,
+						'fit'  => true,
+					),
+					array(
+						'type'  => 'row',
+						'items' => array(
+							array(
+								'type' => 'text',
+								'text' => 'Presented by',
+							),
+							array(
+								'type'  => 'image',
+								'path'  => $this->image(),
+								'width' => 150,
+							),
+						),
+					),
+					array(
+						'type'  => 'list',
+						'items' => array( 'Scan the code', 'Choose a project', 'Share with friends' ),
+						'size'  => 34,
+					),
+					array(
+						'type' => 'text',
+						'text' => 'Every Saturday at noon',
+						'size' => 28,
+					),
+				),
+			);
+			foreach ( array( 'print_pocket_flyer', 'instagram_feed_portrait' ) as $preset ) {
+				$t           = new StackTemplate();
+				$r           = ( new GDRenderer() )->create_canvas( $preset );
+				$boxes       = $t->plan_layout( $r, $data );
+				$paths       = $t->render( $data, $r, array( 'preset' => $preset ) );
+				$this->files = array_merge( $this->files, $paths );
+				$this->assertCount( 1, $paths );
+				$this->assertSame( $boxes[2]['size'], end( $requested ) );
+				$this->assertSame( array(), $t->get_warnings() );
+				$info = getimagesize( $paths[0] );
+				$this->assertSame( $r->get_width(), $info[0] );
+				$this->assertSame( $r->get_height(), $info[1] );
+				foreach ( $boxes as $i => $box ) {
+					if ( $i ) {
+						$this->assertGreaterThanOrEqual( $boxes[ $i - 1 ]['y'] + $boxes[ $i - 1 ]['height'], $box['y'] ); }
+				}
+			}
+		}
+	}
+}
diff --git a/tests/poster-template-smoke.php b/tests/poster-template-smoke.php
index 1d1051358..840508469 100644
--- a/tests/poster-template-smoke.php
+++ b/tests/poster-template-smoke.php
@@ -80,7 +80,8 @@
 $assert( 'core ships the print_tabloid preset', str_contains( $presets_src, "'print_tabloid'" ) );
 $assert( 'core ships the print_tabloid_300 preset', str_contains( $presets_src, "'print_tabloid_300'" ) );
 $assert( 'core ships the print_pocket_flyer preset', str_contains( $presets_src, "'print_pocket_flyer'" ) );
-$assert( 'QR codes resolve through a filter', str_contains( $tmpl_source, "'datamachine/image_generation/qr_image_path'" ) );
+$helpers_source = (string) file_get_contents( $plugin_root . '/inc/Abilities/Media/Templates/TemplateHelpers.php' );
+$assert( 'QR codes resolve through a shared filter', str_contains( $helpers_source, "'datamachine/image_generation/qr_image_path'" ) && str_contains( $tmpl_source, 'TemplateHelpers::qr_image_path' ) );
 $assert(
 	'template names no domain concept or vendor',
 	! preg_match( '/event|venue|rsvp|extrachill|extra chill|ticket/i', $tmpl_source )
@@ -134,6 +135,7 @@ function get_template_directory() {
 require_once $plugin_root . '/inc/Abilities/Media/TemplateInterface.php';
 require_once $plugin_root . '/inc/Abilities/Media/BrandTokens.php';
 require_once $plugin_root . '/inc/Abilities/Media/GDRenderer.php';
+require_once $plugin_root . '/inc/Abilities/Media/Templates/TemplateHelpers.php';
 require_once $plugin_root . '/inc/Abilities/Media/Templates/PosterTemplate.php';
 
 use DataMachine\Abilities\Media\GDRenderer;