if you'd like to cycle through the background images, go to the site and paste this in your URL bar:

  javascript:document.getElementsByTagName('a')[0].onclick=function(e){e.preventDefault();document.body.id=switcher[(switcher.indexOf(document.body.id)+1)%switcher.length]};void(0);

now each time you click the facebook logo, the next background image will load

edit: in related news, it looks like Chrome won't let you paste javascript links into your URL bar. you may need to manually type the 'javascript:' part at the beginning.