How to use the wallpaper on your
desktop background

1. CONTROL + CLICK the image you want to save to your desktop. 
2. You will see the 'SAVE IMAGE AS...' option.
3. Click on that option.
4. Save the image on your desktop. 
5. Go to your desktop and CONTROL + CLICK that image. 
6. You will see 'SET DESKTOP PICTURE' option. 
7. Click on that option