MrDo's site was last updated going on a year and a half ago.
I'm not going to enjoy it when all these 4-bit toys end up unusable by anyone other than hap, but I'm calling it right now that that's what's happening.
Actually the "official" source for MESS artwork is Duke's mess.redump.net AKA mess.org. Mr. Do never officially took it over, although he expressed the intention IIRC.
I'm the last person to update the mess.org wiki page regarding artwork, but I don't particularly want to be "that guy who does the MESS artwork."
Particularly when I'm no Photoshop expert nor .lay file expert.