PC: Right-click on the image. Select the option "Set as Wallpaper" or "Set as Background".
MAC OSX: Control-click on the image and select "Download Image to Disk". Save the image to your hard drive (remember where you saved it!). From your Apple menu, select "System Preferences > Personal > Desktop". Find the image and drag it into the Image Well.
MAC OS9: Control-click on the image and select "Download Image to Disk". Save the image to your hard drive (remember where you saved it!). From your Apple menu, select "Control Panels" and choose "Appearance". Choose the "Desktop" Tab. Click the "Place Picture..." button and choose the image. Drag the drop-down menu labeled "Position Automatically" to choose the desired appearance of the image.
