function intro_slideshow() {
      // element IDs of each photo-containing div
      var slides = [
        "photo2",
        "photo3",
        "photo4",
        "photo5",
        "photo1"
      ];
      
      // Length of time to display image in seconds
      var displayLength = 5;
      
      // Length of time to transition image in seconds
      var transitionLength = 2;
      start_slideshow(slides, displayLength, transitionLength);
    }
    
    safe_addEventListener(window, "load", intro_slideshow);