Open My Pictures
Click the picture you want to use as a desktop background.
Under Picture Tasks, click Set as desktop background.
To open My Pictures, click Start, and then click My Pictures.
You can also right-click the picture, and then click Set as Desktop Background.
If you want to change the way the picture is displayed on your desktop, right-click the desktop, and then click Properties. On the Desktop tab, in the Position box, select a display option.
Change your desktop background
Use personal pictures as a screen saver
File and folder management overview