This is not a direct answer to your question, more like a hint: I don't know if you know this already, but there's an extension to python called pygame. It wraps the SDL libraries and it was made exactly for that: Game programming. I think this tool would make your life much, much easier. If you later need to add a background music or something to your game, pygame will handle all this. Take a look:
www.pygame.org
Drawing an image with pygame is really simple as well ^_^. To enter fullscreen mode (which you may want to use on your game) is also piece of cake
Regards!