David Kaplan, assistant professor of physics at the University of Wisconsin – Milwaukee, sent me this gif, showing the differences between an image of the Andromeda Galaxy produced by astrophotographer Robert Gendler, and the image of the Andromeda Galaxy that serves as the default desktop wallpaper in Apple's OS 10.7 (Lion).

Apple has once again altered the Universe according to their whim. They moved/removed many stars, and got rid of a whole galaxy. This is M110, which is one of M31's [Andromeda's] satellites. The other big satellite, M32, is still there.

Kaplan says he hasn't looked lately, so he can't guarantee that galaxy M110 hasn't actually vanished from the sky. But he's pretty sure it's only really been lost to Photoshop.