<html>
  <head>
    <title>extend_cache example</title>
  </head>
  <body>
    <p>PageSpeed will rewrite this image's source to include a content-hash.
    Note that this requires a background asynchronous fetch of the image;
    therefore the page may not be rewritten the first time.  If it isn't, wait
    a few seconds and reload.</p>

    <img src="images/Puzzle.jpg"/>
  </body>
</html>