PC: Click on appropriate size,
right click image, choose 'Set As Wallpaper/Background'
from Menu. OR right click image,
choose 'Same Image As'
from menu and save in 'My
Pictures'. You will be
able to save multiple wallpapers
and switch between them
by changing the wallpaper
selection of your desktop
properites.
Mac OS 9: Save image, open
Appearance control panel. Select Desktop
folder tab, Place Picture.
Mac OS X: Open System Preferences,
click on Desktop settings. Drag image
from desktop to preview box in Desktop
Preferences window.