/** Stop the slideshow */
 public void stopSlideshow() {
   if (timer != null) {
     timer.cancel();
     timer = null;
     slideshowRunning = false;
   }
 }
 /** Start the slideshow */
 public void startSlideshow() {
   if (timer == null) {
     timer = new LightboxImageTimer();
     timer.scheduleRepeating(slideshowDelayInSeconds * 1000);
     slideshowRunning = true;
   }
 }