hey, go open an image in GC, then export it / save it, now open the format menu.... notice it goes from the top of the screen to the bottem with more to come? There are a LOT of formats GC can handle. One of them might use the .rm extention, or GC might have just claimed it since it did not seem to be 'assinged' to real player, (do what the last person said to do that)
Its just a matter of GC being able to handle so many files, thus having specifications, creator / file type codes, and extentions overlapping in weird ways
-Owl