Q: I'm pretty sure I did everything right, but my game refuses to display this JPEG! It doesn't crash or hang, and the gestalt_Graphics check passes, but it doesn't show the picture. What gives?
A: The problem may be with the JPEG file itself. JPEG is actually a name given to a variety of different image formats, and the Glk implementation you're using may only be equipped to decode some of these. Resaving the JPEG with different settings, or with a different graphics program, may do the trick. If it still isn't working, you may have to use PNG instead.