This is a very interesting and unique idea! I think it could certainly be useful, especially to create glitched or neat images, but I think It could have benefited from "helper" functions/commands buttons. Unfortunately we can't just do random stuff, plenty of things will just break the image. It seems a 1 to 1 replacement works, so I wish there was a one button "scramble" selection. (maybe also a randomize random locations on all the image too) Just throwing out ideas.

Overall it's  a neat project, great job!