Setting PC desktops
Each desktop comes in three sizes: 1280x1024 pixels, 1024x768 and 800x600. Choose the one that's the same size as your desktop, and click on it to download. Once the .exe file has downloaded, run it and the desktop image will be extracted to your c:\windows directory.

To set the image as your new wallpaper, right-click on the Windows desktop, select Properties, click on the Background tab, then select the name of your wallpaper from the Wallpaper window on the bottom right-hand side. Then click OK to install it.