That image is from my fancy new Kindle Paperwhite (yes, that's an affiliate link). How did I take it? It is pretty simple:
- Tap the upper right corner of the screen and the lower left corner at the same time.
- The screen flashes.
- The image is saved at the root of your Kindle Paperwhite.
- Plug your Kindle into your computer and you'll see the images. Drag 'em on your computer and there you go.
I did try this trick on a Kindle Touch, and it didn't seem to work.