Careful with this one - can be slippery when wet. I suppose you what to know how to get it on the desktop now. Setting the background as your desktop wallpaper can be done in a number of ways. 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!Now go to wherever it is you normally set your desktop backgrounds for your computer and selected the saved wallpaper.
Another way is when the full screen wallpaper has loaded, right click it and choose 'save image as...' or 'set as Desktop Background' or 'Set as Background'. You'll know what to do when the time comes. I know you can do this. I bet you already know. I'll button it now.
Return to wallpaper thumbnails.