Image Compare & XOR
Difference, XOR or overlay two images to reveal what changed between them.
Drag one here, or choose a file.
Drag one here, or choose a file.
Spotting what changed between two images
Cache pages that post a pair of nearly identical images are asking you to find what changed. Subtracting one from the other answers that in a single step: everything they share goes black, and the difference is all that's left. If the result looks entirely black, turn the amplify slider up before believing it. Differences of one or two levels are invisible otherwise.
Overlay handles a different puzzle. In visual cryptography, a message is split into two sheets of random noise, each meaningless alone. Laid on top of one another, wherever either sheet is dark the result stays dark, and the message appears. That is exactly what this mode computes.