title: loading images from GPX file - iOS MapKit CS193 example
body: <p>I'm following the example given in CS193p lecture 14 MapKit. I managed to load a gpx file (vacation.gpx that the lecturer used), but it only shows red pins and callouts without thumbnail and images when I click callouts.
  In the original gpx file, all links work fine. How can I make it work? Please help.  </p>