The Kindle Touch (non-ad supported) comes with 20 attractive gray-scale screensaver/wallpaper images.
They're fine, but after a while, I wanted to see some different images. One of the reasons I got the ad-free Touch was so that I wouldn't be assaulted with an ad every time I picked up my Kindle to read something. I returned the ad-supported Kindle 3 because -- among other reasons -- although I can take ads in magazines, I didn't want to see them in a book -- not even an e-book.
The web is full of Kindle-supported screensaver images that I would have preferred to see on my device, but Amazon doesn't allow me to customize the Kindle in even that harmless way. And this annoyed me.
So I took matters into my own hands, did a bit of hacking on my Kindle over the weekend, and now I have a pool of about 200 attractive, varied, and unusual images I can use as screensavers on my Kindle, as the following gallery shows. Tomorrow, a post on how I did it.