Select a wallpaper below by clicking on the image. From the browser window, right click and save the image to your computer. Unless, of course, you don't need to keep around a hard copy for later use. If this is the case (and you are on a PC), you can simply right click and select "Set as Wallpaper" (make sure the picture display is set to fit the screen).
The tiles are shown at full size, so you only need to right click and "Set as Wallpaper" (don't forget to set your picture display to tile!). If you are using a Mac, you will need to save the image to your computer before you can "Set Desktop."
All new wallpapers are offered in widescreen as well as the original fullscreen. When you click on a thumbnail of a new wallpaper below, it will take you to a page offering both styles. Then simply click on which style you would like.