Right click the picture, and save it. Remember what folder it saves in. It is usually in the "my pictures" folder.

Then, on your computer, find the picture, and right click it. Choose "open with" then "windows picture and fax viewer.

When the picture opens, right click it and choose "set as desktop background."

Now, if your picture is tiled, and you don't want it that way, it is easy to fix. just go to your desktop, and right clik any OPEN spot, not a spot with an icon. Just right click any unused spot ont he desktop and go to "properties" the go to the "desktp" tab at the top, ad click it. There you will see a dropdown box on the right with choices like, tile, stretch, or center. Play around with those settings until you get what you want.

any questions?