Question 1

How does the tool tell two images are duplicates?

Accepted Answer

Each image is shrunk to a tiny grayscale grid and turned into a "fingerprint" (a perceptual hash) based on how brightness changes across that grid. Images with identical or very similar fingerprints are grouped together, even if they were saved at different sizes or compression levels.

Question 2

What's the difference between "Exact" and "Similar" groups?

Accepted Answer

"Exact" means the two images produced the exact same fingerprint — they're visually identical (a copy, a re-save, a different format of the same photo). "Similar" means the fingerprints are close but not identical, which usually means a crop, recompression, resize, or minor edit of the same photo.

Question 3

Will this catch photos that are similar but not the same photo?

Accepted Answer

It's tuned for near-duplicates of the same shot (resaves, crops, small edits), not generally similar scenes. Two different photos of the same subject usually won't match unless they're nearly pixel-identical.

Question 4

How many photos can I scan at once?

Accepted Answer

Up to 300 images in a single batch. Everything is processed in your browser tab, so very large batches are capped to keep things fast and avoid running out of memory.

Question 5

Are my photos uploaded anywhere?

Accepted Answer

No. Every image is read and hashed locally using the Canvas API — nothing is sent to a server, and photos never leave your device.

Question 6

Does the tool delete files for me?

Accepted Answer

No. It only identifies which images are duplicates so you can review them and remove the ones you don't want yourself — nothing is deleted automatically.

Duplicate Image Finder

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Frequently Asked Questions

How does the tool tell two images are duplicates?

What's the difference between "Exact" and "Similar" groups?

Will this catch photos that are similar but not the same photo?

How many photos can I scan at once?

Are my photos uploaded anywhere?

Does the tool delete files for me?

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