User Guide Local Files

Local Files Search

The Local Files tab finds cover images that already exist in your image folder by comparing filenames with the selected ROM. It is the fastest and completely offline way to fill gaps — for example when your covers use slightly different names than your ROMs.

How it works

1. Select a game in the missing covers list. The local search runs automatically for every selected game.
2. FindRomCover compares the ROM name (or MAME description) against the image filenames in the top level of your image folder. With Ignore Bracketed Text in Matching on (the default), region and revision tags such as (USA) and [En] are ignored on both sides.
3. Images whose similarity score is at or above the configured threshold are listed, ranked from best to worst.
4. Click an image to save it as the cover: it is converted to PNG if necessary and stored as the sanitized [gamename].png.

For large collections a trigram index pre-filters candidates so that only plausible matches are compared in detail.

Similarity algorithms

Choose the algorithm under Set Similarity Algorithm:

Algorithm	Best for	Notes
Jaro-Winkler Distance	Most collections (default)	Rewards common prefixes; tolerant of small differences
Jaccard Similarity	Filenames with reordered words	Compares sets of character n-grams
Levenshtein Distance	Strict edit-distance matching	Counts insertions, deletions, and substitutions; early-exit optimization

See Similarity Algorithms for guidance on choosing and tuning.

Similarity threshold

Set Similarity Threshold sets the minimum score (10%–90%) an image must reach to appear in the results. The default is 70%.

• Raise it (80–90%) for precise matches and short result lists.
• Lower it (40–60%) when filenames differ a lot, for example when your images use full game titles and your ROMs use abbreviations.

The threshold also pre-filters the candidates sent to AI Vision Assist, where a separate Candidate similarity value is configured — see AI Settings.

Result list

Each result shows the image preview itself, the filename, and the similarity score. The preview size follows Set Thumbnail Size (100–500 pixels); there is no separate hover preview.

Actions:

• Left-click an image to use it as the cover.
• Right-click an image for the context menu:

Menu item	Action
Use This Image	Saves the image as the cover for the selected game
Copy Image Filename	Copies the image filename (without extension) to the clipboard
Open File Location	Opens the containing folder with the image selected (Windows and macOS) or opens the folder (Linux)
Open File	Opens the image in your default viewer

AI Pick Best

When AI Vision Assist is enabled, the AI Pick Best button sends the top-ranked local candidates to a vision model, which chooses the best-looking cover. The winner is moved to the front and marked with a green AI badge. Depending on your settings the pick can be saved automatically. See Picking Covers.

Troubleshooting

Symptom	Solution
No results	Lower the similarity threshold, switch algorithm, or verify the image folder contains covers in its top level
Wrong image ranked first	Raise the threshold or use AI Pick Best
Results take long on a network drive	Copy the image folder to a local disk
A cover is never matched	Rename the image to match the ROM, or assign it manually from the list

Related pages

• Similarity Algorithms
• Image Handling
• Missing Covers List
• AI Vision Assist