Careful with this one - can be slippery when wet. I suppose you what to know how to get it on the desktop now. There are a few ways to get the wallpaper to be your desktop background. You can either right click background wallpaper below and then click 'save target as...' (IE & Opera) or 'save link as...' (Firefox). Please remember where you save it to!Next goto your computers display control panel and set the background to the image you just saved.
A different way altogether is to right click the background below, from here choose 'save image as...' or 'set as Desktop Background' or 'Set as Background'. You'll know what to do when the time comes. I have faith in you. My guess is you already know. I'll keep a lid on it now.
Return to wallpaper thumbnails.