$(function() {
  setInterval("slideFade()", 6000);
});

function slideFade() {
  var $active = $("#slideshow img.active");
  if ($active.length == 0) $active = $("#slideshow img:last");
  var $next =  $active.next().length ? $active.next() : $("#slideshow img:first");

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

  $next.css({opacity: 0.0}).addClass("active").animate({opacity: 1.0}, 2000, function() {
    $active.removeClass("active last-active");
  });
}