This looks to cool I didn't know anything about perceptual hashing but the idea makes a lot of sense. I'm curious if the system lose its effectiveness if a user shifts an image a few pixels, reflects it, or apply a certain filter that makes all pixels have a slightly different tonality. I'm also thinking of some system maybe a small ML program that applies a minimal amount of noise to the image such that to the human eye it looks the same but pixel-wise is totally different.