function slideSwitch() {

var $active = $('#slideshow IMG.active');

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

// use this to pull the images in the order they appear in the markup
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}, 700, function() {
        $active.removeClass('active last-active');
    });
}