// orig via: jonraasch.com
function update_image() {
  var $active = $('#slideshow DIV.active');

  if ( $active.length == 0 ) $active = $('#slideshow DIV:last');

  // use this to pull the divs in the order they appear in the markup
  var $next =  $active.next().length ? $active.next()
      : $('#slideshow DIV:first');

  // uncomment below to randomize
  // var $sibs  = $active.siblings();
  // var rndNum = Math.floor(Math.random() * $sibs.length );
  // var $next  = $( $sibs[ rndNum ] );

  $active.addClass('last-active');

  $next.css({opacity: 0.0})
    .addClass('active')
    .animate({opacity: 1.0}, 1000, function() {
      $active.removeClass('active last-active');
    });
}