If your background image is a vertically aligned sprite sheet, you can horizontally center each sprite like this:
#doit {
background-image: url('images/pic.png');
background-repeat: none;
background-position: 50% [y position of sprite];
}
If your background image is a horizontally aligned sprite sheet, you can vertically center each sprite like this:
#doit {
background-image: url('images/pic.png');
background-repeat: none;
background-position: [x position of sprite] 50%;
}
If your sprite sheet is compact, or you are not trying to center your background image in one of the aforementioned scenarios, these solutions do not apply.