This is why like me, you're not a cryptographer. AES256 is a cipher, its one component of a cryptosystem. Analysing cryptosystems is a complex area that does not involve vetting software for buzzwords.

I can take AES256 and make it output the image here: https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation...

That's not supposed to happen. The part where homebrew diverges from cryptography is that the former involves engineers like us connecting buzzwords together to produce images like the Wikipedia article, the latter involves complex math and rigorous peer review.