What is visual regression testing?+
Visual regression testing automatically compares screenshots of your UI before and after a code change to catch unintended visual differences. Tools like Percy and Chromatic use pixel diffing. This tool lets you do manual diffs for quick checks.
How does image differencing work?+
The tool compares each pixel's RGB values between the two images. Pixels that differ are highlighted (often in red or pink). The diff mask shows which parts of the image changed and by how much.
What if my images are different sizes?+
The tool scales the smaller image to match the larger one before comparing. For accurate diffs, use images captured at the same resolution and zoom level.
Can I detect subtle colour changes?+
Yes. Adjust the sensitivity threshold - a lower threshold flags even minor colour shifts (useful for print quality checks). A higher threshold only flags visually obvious differences (useful for UI regression).