Most of the really common images in iOS are tucked away in .artwork files. These files typically contain hundreds or thousands of images, all rolled into one file. I assume Apple does this for performance reasons. If you have an iOS SDK handy, you’ll find a number of .artwork files lying around.

My iOS Artwork Tool can both extract images from, and import images into, .artwork files. You don’t need to be a registered iOS developer to use the tool — it’s a simple Python command-line app.

I’ve just updated the tool to support iOS6. As it turns out, a lot of things changed. There are now two different .artwork formats: a hard-to-crack old-style format found in iOS5 and earlier, and a surprisingly easy-to-crack format introduced in iOS6. The tool now supports both formats.