Image Diff
Compare two images and highlight every pixel that changed.
Exactly Which Pixels Changed
Drop in two versions of an image — a design revision, two screenshots of a web page, a photo before and after retouching — and see every pixel that differs. Highlight marks each change in red over a faded copy, with a box around the changed area; Difference shows the raw per-pixel difference.
Swipe and Fade let you compare by eye, and a tolerance slider ignores tiny changes such as JPEG compression noise. The panel reports the percentage and count of changed pixels, the largest change and where it is.
Key features
- Four views — highlight, difference, swipe and fade.
- Tolerance control to ignore compression noise.
- Statistics — changed pixels, percentage, largest change and bounding box.
- Different sizes handled — B is scaled to A.
- Download any view as a PNG for a bug report.
This tool runs entirely inside your browser using native Web APIs. Your files and text are never uploaded to a server, never logged and never shared with third parties.
How to use: Image Diff
- Add image A
The original or expected version. - Add image B
The changed or actual version. - Adjust tolerance
Raise it until noise disappears but real changes remain. - Switch views
Swipe and Fade help judge the change by eye.
Technical specifications
| Processing location | Entirely in your browser — no server round trip |
|---|---|
| Data uploaded | None. Files and text never leave your device |
| Price | Free — no account, no trial, no usage cap |
| Category | Media |
| Works offline | Yes, once the page has loaded |
| Browser support | Chrome 90+, Edge 90+, Firefox 90+, Safari 15+ |
| Interface languages | English, 中文, हिन्दी, Español, العربية |
Frequently asked questions
Why are lots of pixels different in two identical-looking JPEGs?
JPEG compression changes pixel values slightly every time an image is saved. Raise the tolerance until those tiny differences disappear and only the real edits remain.
Can I compare images of different sizes?
Yes. Image B is scaled to the size of image A before comparing. For exact results, compare images at the same resolution.
What is visual regression testing?
Comparing screenshots of an interface before and after a code change to catch unintended visual changes. This tool does the comparison by hand; automated suites do the same pixel diff in CI.
What does the Difference view show?
The absolute difference of each colour channel, amplified three times so small changes are visible. Black means identical; brighter means more different.
Are my images uploaded?
No. Both are compared in your browser, so confidential designs and screenshots stay on your device.