[DustyPorViva]

Cheating :o
Or at least, that's what people used to do it for...(this is not a valid argument, please do not take it as such.)
Either way, if servers implement that whole set your own states.png thing... I believe it will work, even if the file is not uploaded, if the file IS in the appropriate Graal folder. I tested out a tileset online(using graphics that were saved in my Graal folder, not uploaded) before I bothered uploading the whole thing for others to see it.