function slideSwitch() {
  var $active = $('#right_box IMG.active');

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

  var $next =  $active.next().length ? $active.next()
  : $('#right_box IMG:first');

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

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

$(function() {
  setInterval( "slideSwitch()", 5000 );
});