Wallpapers for your desktop . Right click on the picture and click on set as background .

Choose your desktop size :
800 x 600 / 1024 x 768

If you are not sure what your desktop size is , follow the instructions below :

Click on the Start menu
Click on Control Panel
Click on Display
Click on the settings tab located on the top
Check the slider at the bottom left .
Thats your screen size .