$(document).ready(function() {
  $('#slideshow').append(Drupal.settings.csextra_images.pop());
  $('#slideshow').cycle({ 
    fx:      'fade', 
    sync:     true, 
    speed:    2000,
    timeout:  4000, 
    before:   onBefore 
  });
});

function onBefore(curr, next, opts) {
  if (Drupal.settings.csextra_images.length > 0 && opts.addSlide) {
    opts.addSlide(Drupal.settings.csextra_images.pop());
  }
}