On the Desktop tab, do one or more of the following:
Click a picture in the Background list. In Position, click Center, Tile, or Stretch.
Click Browse to search for a background picture in other folders or on other drives. You can use files with the following extensions: .bmp, .gif, .jpg, .dib, .png, .htm. In Position, click Center, Tile, or Stretch.
Select a color from Desktop color. The color fills the space not used by a picture.