title: Optimizing the load of numerous images
body: <p>I have a website that displays about 30 fairly small color gif files on the main page. When looking into optimizing the site, I ran Google's PageSpeed Analyzer. It suggests that I create a CSS sprite for them. The problem that I'm running into is that the main page does not show the same 30 images per user and/or per page load. Also, the images are replaced about once a month. </p>
  
  <p>I was thinking maybe a dynamic generation of a CSS sprite or a CSS sprite that contains all possible images. I am looking for the most efficient way of accomplishing this.So my question is, What can I do to reduce the requests or optimize this aspect while allowing for the change described?</p>