title: Get Different Images from one URL
body: <p>For example, </p>
  
  <p><a href="http://placeimg.com/640/480/people" rel="nofollow">http://placeimg.com/640/480/people</a></p>
  
  <p>is one url. If you reload the page, it comes with a new image.  My website has a background image, and I want it to be a random image of two images:</p>
  
  <p><a href="http://bit.do/bgimage1" rel="nofollow">http://bit.do/bgimage1</a></p>
  
  <p><a href="http://bit.do/bgimage2" rel="nofollow">http://bit.do/bgimage2</a></p>
  
  <p>How can I achieve this? And the calling of the image in the css.</p>