Highlight the Difference Between Two Images

What a pixel difference shows

An image difference (or 'image diff') compares two pictures pixel by pixel and shows you exactly where they disagree. It's the precise counterpart to the eyeball test: instead of squinting at two thumbnails, you get a single overlay where changed pixels are painted in a bright colour and the unchanged background is dimmed to grey.

This tool also reports the percentage of the image that changed, and a threshold slider lets you ignore tiny differences from JPG compression or slight colour shifts. It's ideal for spotting edits, catching visual regressions in screenshots, verifying exports, and proofreading designs.

How to find the difference between two images

1. Add both images. Drop them into slots A and B. For an exact diff they should be the same size.
2. Set a threshold. Raise it to ignore compression noise, lower it to catch the faintest change.
3. Find differences. Click the button — changed pixels light up and the percentage appears.
4. Download the overlay. Save the highlighted difference image if you need to keep or share it.

Tune the threshold

If two JPGs of the same scene show diff noise everywhere, raise the threshold until only the real change remains. For pixel-perfect work like UI screenshots, drop the threshold to zero so even a single off pixel is flagged.