Click and select the image with your corresponding screen (monitor) resolution. (To find your screen resolution setup, select Display from the Control Panel options).

Once the large image is displayed, right click your mouse over the image and select "Set as Background".

You may need to adjust your Windows Desktop settings: Right-click the desktop image and select Properties (or select Display from the Control Panel options). In the Wallpaper box, make sure that the "Center" option is selected (instead of Tile).