Image Diff Tool

For every pixel, the tool subtracts the red, green and blue values of the second image from the first and keeps the absolute difference. The result is displayed as a Difference Map: pixels that match exactly are black, small changes appear as dark tones, and large changes show up bright. The color in the map tells you which channels changed.

Drop two images onto the upload area, or click it and select both files at once. Their names appear in the list and the Compare Images button becomes active. Click it, and the Difference Map appears below the button. If you select more than two files, only the first two are compared, so pick your pair carefully.

The tool compares them at the smaller width and the smaller height of the pair, scaling each image to fit that size. This works well for two versions of the same photo exported at slightly different sizes, but images with different aspect ratios or crops will be stretched and show differences everywhere. For precise results, compare files with identical dimensions.

It works at the level of individual pixel values, so even a change of one level in one channel registers, although very small differences appear almost black. To see faint changes, such as subtle JPG compression or slight color shifts, save the map image from your browser and raise its brightness or contrast in an editor.

Use it to confirm exactly what a retoucher changed, check that a re-export matches the original, compare noise reduction or sharpening settings, or see how much a platform's compression altered your upload. It is also a quick way to verify that two seemingly identical files really are the same before deleting duplicates from an archive.

Yes. It is free and needs no software. Both images are compared in your browser on your own device and are never uploaded, so unreleased client work stays with you. To open the tools, you answer once that you are a photographer and create or log into a free Imagen account, which unlocks every tool.