I noticed that /background deals with whatever you throw at it when it comes to images. No file extension? No problem. Wrong file extension? No problem.
On the other hand, /drawpic and $pic seem to more or less require file extensions to work. BMP files being the main exception, although $pic returns 32 width/height for no extension BMP files.
What I'm basically asking is; could we get /drawpic and $pic to work like /background? Just go for the signature from the start, or at least when there's no file extension.