• Right mouse click on the wallpaper image above
• If available, choose "Set as Wallpaper"
• If not, choose "Save Image As", then choose a file name and add ".jpg" (Save the image to your desktop so it is easy to find)
• From the Start menu, go to Settings, Control Panel, then Display, then Background - choose "Browse", go to "Desktop", then open the "jpg" file and Click "OK"

For Mac OS 8 & Mac OS 9: 

• Save the wallpaper image above to your desktop or hard drive
• The desktop appearance prefences panel is accessed differently between Mac OS 8 and Mac OS 9
• For Mac OS 8 go to the Apple menu, select "Control Panel" followed by "Desktop Pictures"
• For Mac OS 9 go to the Apple menu, select "Control Panel" followed by "Appearance". Of the five tabbed sections in this "Appearance" window choose "Desktop".
• Drag the image from your desktop/hard drive to the desktop pictures preview window
• Select "Tile on Screen" from the "Position" pop-up menu
• Click "Set Desktop"

For Mac OS X: 

• Holding Ctrl and clicking the image simultaneously, choose "Download Image to Disk"
• Save the image to your hard drive preferably in the Library | Desktop Pictures folder
• From the "Finder" menu choose "Preferences"
• In the "Preferences" window, click "Select Picture" and navigate, using the file explorer that opens for you, to your wallpaper image
• Click "Choose" to confirm your choice