Image Diff: Compare Two Images
Compare two pictures pixel by pixel and highlight what changed.
Runs in your browser Your input never leaves your device.
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About this tool
Choose a picture A (before) and a picture B (after) and the tool shows them with a third picture where every pixel that differs is painted pink over a faded copy of the original, plus the number and percentage of pixels that changed. It uses pixelmatch, a small, well-known library built for visual regression testing. Sensitivity sets how different two colours must be to count: at its lowest every change counts, at the default tiny differences from compression are ignored. Tick Ignore anti-aliasing differences to skip pixels on slightly shifted edges of text and shapes. If the pictures have different sizes, B is scaled to the size of A and the tool says so; for a meaningful comparison use pictures of the same size. Pictures up to 4 megapixels are compared. We tested with pictures where a block of known size was changed: the count was exact, a one-step colour change was ignored at the default and found at zero sensitivity, and different-size input is refused by the library check. The picture is processed in your browser and never uploaded.
How to use it
- Choose picture A and picture B.
- Adjust the sensitivity if needed.
- Read the count and look at the pink areas.
- Download the difference image.
Common problems
- It says almost everything differs
- The pictures may be different sizes or slightly shifted. Compare pictures taken the same way, at the same size.
- Small differences are not shown
- Lower the sensitivity slider towards 0 to include tiny colour changes.
- JPEG noise is shown as differences
- Compression adds noise. Raise the sensitivity threshold, tick Ignore anti-aliasing, or compare PNG files.