Skins don't come in jpg format. They are bmps. If you wish to make your own skins, you can go into AH, in the hangar, select the plane you want, and right click and choose "Save default skin..." or "Save skin" or something like that. Then check in your Aces High II\Skins\ directory for a subdirectory with the name of the plane you chose. It will have a lot more files than you need (you don't need all the damage, pilot, instrument, etc, files, just the ones that show the plane's fuselage and wings, and/or cockpit)
