Windows:

Click the image size that's closest to your current monitor resolution. You can find your current monitor resolution by right clicking on your desktop, selecting 'Properties', clicking on the 'Settings' tab, and looking in the box labeled 'Screen area'.

Once the image has downloaded, right-click on the image and select 'Set as Wallpaper'.

You can adjust the settings for your wallpaper by right-clicking on your desktop and selecting 'Properties'. Click on the 'Background' tab and look in the box labeled 'Wallpaper', and you'll be able to adjust your settings.

Macintosh:

Click the image size that's closest to your current monitor resolution. You can find your current monitor resolution by opening the 'Monitors & Sound' (MAC OS 8.6) or 'Monitors' (MAC OS 9.0) control panel from the Apple menu.

Once the image has downloaded, click and hold your mouse button and select 'Download this Image to Disk' (Internet Explorer) or 'Save this image as...' (Netscape). Remember where you save the image, since you might want to put all your wallpaper images in the same place.

Open the 'Appearance' control panel from the Apple menu and click the 'Desktop' tab.

Click 'Place Picture...' and navigate to where you saved the wallpaper, then select the image and click 'Choose'. If you click 'Set Desktop', you'll be ready to enjoy your wallpaper!