Adds a pixel-level image diff to the image viewer on GitHub and GitLab — next to 2-up, Swipe and Onion Skin.
Users
11
+9 in 30 days
Rating
0.0 / 5
unchanged in 30 days
Ratings
0
0 in 30 days
Store rank
#189K
#158K among extensions
Version
0.19.0
updated 16 Oct 2026
Users
monthly, 1 months
Latest, 16 Oct 2026:11 usersMove the mouse over the chart for any month
Ratings count
monthly, 1 months
Latest, 16 Oct 2026:0 ratingsMove the mouse over the chart for any month
The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.
About GitHub Pixel Diff
GitHub and GitLab both show you two versions of an image. Neither shows you what changed between them.
Pixel Diff adds a fourth mode next to 2-up, Swipe and Onion Skin — in GitHub's image viewer and in GitLab's merge requests. It compares the two images pixel by pixel, paints every difference red, and crops the result to the area that actually changed — so a three-pixel shift in a long screenshot is a three-pixel shift you can see, not a picture you have to hunt through.
- A threshold slider: raise it to ignore compression noise, lower it to catch everything.
- Before / after / diff, and all three side by side, sharing one scale and one crop.
- Images that changed size are aligned and compared anyway.
- SVG and other vector images are rasterised before comparison.
- Works on the images the site has already loaded — nothing is uploaded anywhere.
- A GitLab of your own: add its address on the settings page, grant access, and the mode appears in that instance too.
- No merge request at hand? Two images of your own compare the same way at https://nemo-illusionist.github.io/gh-pixel-diff/
The comparison runs in your browser, in a background thread. The extension has no server, collects nothing, and sends nothing.
Open source: https://github.com/Nemo-Illusionist/gh-pixel-diff