Steganography is a (fascinating) bitch. There are a lot of ways to hide a message in an image which is very resilient to manipulations like resizing, compression or even the loss of information by actually filming a screen versus taking a screen capture.

If you adjust your approach to not rely on a single picture to reliably convey a short message, but part it out over tens or hundreds of frames in a video, it’s basically impossible to make sure that the message was erased without knowing the algorithms used or rendering the video unwatchable.

It’s an awesome field and nothing new.