Possibly one of the most intersting ones on the site. Yawn! 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. One way is to right click the desktop background below and then choose 'save target as...' (IE & Opera) or 'save link as...' (Firefox). Don't forget where you saved it though! Next you need to go to where your computer's operating system display settings and set the image as your background / wallpaper.
Another way is when the full screen wallpaper is shown, right click it and select 'save image as...' or 'set as Desktop Background' or 'Set as Background'. It'll come to you when the time is right. I think you have it in you. My guess is you already know. I'll shut up now.
Return to wallpaper thumbnails.