hey thoth! welcome aboard. [img]smile.gif[/img]
have you downloaded dungeon craft? i believe that there are example files for each of the types of the graphics for each of the sizes in the the game. they can be of any color depth (up to 32 bit). there are all kinds of directions that come with the download, but if you just look in the default.dsn directory, you'll see what i'm talking about.
if this isn't helpful, i could probably be more specific, so let me know.
[img]graemlins/mage1.gif[/img]