Go to Start > Run, then type "regedit" in the run box. Navigate to the wallpaper entry: HKEY_USERS > .DEFAULT > Control Panel > Desktop

Double click the wallpaper value. Type in the full path of your image and the filename. The wallpaper graphic must be a bitmap file (.bmp), not a JPEG or other graphic format.

To find the path, go to the image you want. Right click the image and select Properties from the drop down menu. Look for the path next to the word "Location" in the Properties window. Remember that the filename will need to be written after the last place in the path. Separate this by using a \ backslash mark.

You can set your image to be either tiled or stretched across the screen. If you want to tile the image set the TileWallPaper value to 1. If you want to stretch the wallpaper set the WallPaperStyle value to 2. Another way to get the wallpaper tiled is to set the TileWallPaper value to 1

Close the registry and restart your computer. You will notice the changes when you log off or upon restart.