function swapImagesMaps(){
var $active = $('#slideshow .active');
var $next = ($('#slideshow .active').next().length > 0) ? $('#slideshow .active').next() : $('#slideshow img:first');
$active.fadeOut(function(){
    $active.removeClass('active');
    $next.fadeIn().addClass('active');
    });

}

setInterval('swapImagesMaps()', 4000);