Just noticed that for all of their images in their search (eg, the logo, google checkout logo, custom crosses, etc), they are all on 1 image, that is aligned to show that image in each case.) Presumably this is how they manage to achieve faster loading times when loading the images?
It's called "Sprites", i also use them in things like rollover buttons not only because the page loads faster but to avoid onmouseover events, flicker while the second image loads etc.