Windows

1. Right-click on the image and select "Set As Wallpaper" from the pop-up menu

Mac OS 9

1. Control-click and select "Save this Image as" from the pop-up menu
2. Save the image to your desktop
3. From the Apple menu select the "Appearance" control panel
4. Select "Place picture" and locate the wallpaper you downloaded
5. Click "Set Desktop"

Mac OS X

1. Control-click and select "Download image to Disk" from the pop-up menu
2. Save the image to your desktop
3. From the Apple menu, go to System Preferences > Personal section and select "Desktop"
4. On the "Collection" pulldown menu, select"Choose Folder" and locate the wallpaper you downloaded