Introversion

I've tried many different methods to change the sprites of the Multiwinians and it just doesn't work... I've saved it in the .bmp formats as well, but it all just goes back to normal Multiwinians when i get ingame. Is there something I'm doing wrong, like... what type of .bmp should I be saving these as, 16-bit, 24-bit, 32-bit?

Edit: Nevermind... I forgot to delete the first Darwinian.bmp, the other one was darwinian copy.bmp...