It seems like other people have built solutions that use steganography with the image pixels themselves, given that I see examples on Wikipedia.

I can't be remotely useful with the text stuff, though, my coding skills are such that I still have trouble generating token frequency histograms from text files and my most persuasive "chatbot" relayed an entirely pregenerated script to the user, only took 1 bit of user input, and was written on a graphing calculator. (I still got my Theory of Knowledge to feel empathy for it and be unwilling to let me delete it in exchange for a cookie, though, so it did prove my point that people can feel empathy for morally irrelevant things, like a program shorter than your above comment.)