for mac
1) click on the appropraite link for your monitor resolution
2) place file anywhere you like
3) in your "Appearance" Control Panel you can "Place Picture"
4) That's it
for windows
1) click on the appropraite link for your monitor resolution
2) when the picture loads inyour browser window right click on the picture
3) select "Set as Wallpaper"
4) That's it