I uploaded some cover art from taking photos with a Canon DSLR (yeah for foil!), and figured it'd be nice to upload the raw images as well, in case someone wants to spend some time with the images to(e.g.,) get the colors a little better.
But the upload page won't take CR2 files. Probably I could find a way to convert to DNG, but that doesn't appear to be supported, either.
Of course, there isn't really a good way to mark them as raw files, either.
Maybe this is just beyond the scope of MB (or the Cover Art Archive)?