Though the idea is awesome it would take a relatively short time to write a program to tell TPT to write individual pixels from a grid of known element colors.
Similarily you wouldn't even need Photoshop to reduce an image to only those particular colors, and even less so if the program were set to generalize each color it encounters to match the closest known element color.
i made that program, but it requires hour to generate and i dont know that really works lol i think its because i dont know how save it to stamp, so im saving it to code and pasting to TPT code lol