Oh, I know it’s impossible to do something like that. There’s a reason that whenever I upload a photo I always crop it. That way, if there’s ever a question about copyright, I can simply reveal a portion that was cropped. Likewise, someone taking such a photo should keep the untouched, uncropped original in a safe place. You know spicy photos will be used in a questionable way, so this will make it easier for the original owner to refute any modifications.