You can't use ALT S for screen shots in the film viewer. You have to hit the "print screen" button on your keyboard which will save a screen shot to the "clipboard". You then much use an art program (windows paint works) to save each picture BEFORE you print screen again (each print screen clears the previous one). You can also use some other screen capture program like FRAPS to do the same thing.
Hitting ALT S in game will save a screen shot to your Aces High II game folder.
Uploading squad art, logos must be 64x64 bmp files no larger than 6K 256 colors. The squad CO uploads them in the game in the "OClub", "Squads" section. Once it's uploaded it has to be approved by Skuzzy then it will be added (it could take a couple weeks depending how busy Skuzzy is).