This project hasn't been updated in two years. A couple of active alternatives:

https://github.com/BBC-News/wraith Wraith: A responsive screenshot comparison tool.

https://github.com/garris/BackstopJS BackstopJS: visual regression testing by comparing DOM screenshots over time.

https://github.com/Huddle/PhantomCSS PhantomCSS: Visual/CSS regression testing with PhantomJS.

There is also Sikuli http://sikulix.com (Desktop-based) and Kantu https://kantu.io (Chromium-based) for visual regression testing. While these two are primarily for automation, one can use the FIND (image, similarity) commands to compare certain parts of the website with given templates.

Depending on the use case, checking just key parts of the website can even work better and create more stable test cases than whole website checks.

It's been replaced by Jest: https://facebook.github.io/jest/

Correct me if I'm wrong, but I don't believe that's quite accurate. Jest does snapshot testing[0], but that isn't screenshot regression testing.

[0] http://facebook.github.io/jest/docs/tutorial-react.html#snap...

A couple of weeks ago, idle speculation led me to discover both the existence of screenshot-diffing QA as well as some other options:

https://news.ycombinator.com/item?id=13136205

Looks like Facebook doesn't use this anymore. I wonder what they replaced it with?

For people interested in this topic/catching visual regressions take a look at Kontrast

https://github.com/harrystech/kontrast

I tried to set up a system like this for catching differences between browsers but eventually gave up. I used selenium which didn't work well at all as the browsers constantly lost connection ur hung. I think testcafe [1] looks like a promising alternative. Image diffing is the simplest part but getting consistent images to compare can be tricky. Automatically finding regressions with few false positives ain't easy. [1]: https://github.com/DevExpress/testcafe

I have used https://ghostinspector.com/ which is a fremium alternative.

FYI: Halted project.