Obligatory https://m.xkcd.com/1053/ reference, but you're taking this in good stride and that's excellent. :)

If you want to go further down this direction there are all kinds of cool things you can do. There are ways to like XOR bitmaps so pixels which aren't identical show up as white and the rest are black, and the like; if you're working with something else you can look into perceptual hashing although that's a lot more computationally expensive.

Oh! And edge detection! Canny edge detectors are cheap and deterministic and wonderful for all manner of this storm.