There are ways to fool the system, but with millions of pixels and millions ( or hundreds of millions ) of binary numbers in a photo, simple modification is not enough to fool the system. There is still enough of a signature on the photo to match it up. Example : If I know you and and see half a photo of your face I could still recognize you, I may even still recognized that it is you from a quarter of a photo. I might not recognized it is your photo if I just see an ear or nose. A computer is much better at recognizing part of a photo, but there is a point where there is just not enough information for it to work on. Tin eye is a very simple photo recognition system. There are professional photo recognition companies that track copyright photos so that the owners are paid a royalty on the photo.
