I think we definitely need somewhere to document the image formats.
Preferably both a custom page on the doxygen area and a thread here.
(Evidently I don’t know enough about the formats to contribute.)
Now that you’ve pointed out that link I do vaguely remember that discussion. So much has happened since then that it completely slipped my mind.
I very nearly suggested this in my last comment but decided not to mention it since I knew you were the img2pok author and you hadn’t been in the conversation until now. (And I was in a rush.)
A warning on pok2img would be an excellent idea since I suspect many people won’t stop to read the documentation, but they might stop if the image encoder tells them about the possible problems.
Learned this the hard way when working on Blocky World a while back. Some of the GUI images had odd widths, and I had random black lines popping up all over the place. Kind of an annoying bug in PokittoLib, but not that hard to circumvent