Most of us are familiar with the diff command, which compares files and outputs their differences. Diff is particularly useful for managing software patches and maintaining application builds. While that applies solely for text data, what if there was a similar tool for images? Meet Dify, a diff clone for comparing bitmap images. Throw a pair of images in PNG or JPEG and Dify will instantly generate diff.png with all detected differences depicted in red.
That’s basically all Dify can do, but since it worked quite fast and had a number of configuration options worth trying, we spent more time playing with Dify than we had planned. The program is perfect for detecting subtle differences between nearly identical images: a few added pixels, altered text on a screenshot, removed watermarked and more. For example, if you created an original image that went viral online, you can now use Dify to check if someone in the chain has altered it.