The first nine pictures, I got off of the Internet, and then edited myself. The last three i got off of www.splintercell.com, and are not my "works of art", and so I do not credit myself.
Click a picture, and wait for the picture to load. After it loads, right-click the picture, and select "Set as Background." You may be able to get the picture larger by hovering your cursor over the picture and waiting for a small icon to appear at the bottom-left. Click that, and the picture will be full-size. Then right-click and set it as your background.