$(function() {
    var imgWrapper = $('.slideshow > img');
    // only show the first image, hide the rest
    imgWrapper.hide().filter(':first').show();

    $('ul.recentlist li a').click(function() {

        // check if this item doesn't have class "current"
        // if it has class "current" it must not execute the script again
        if (this.className.indexOf('current') == -1) {
            imgWrapper.hide();
            imgWrapper.filter(this.hash).fadeIn(500);
            $('ul.recentlist li a').removeClass('current');
            $(this).addClass('current');
        }
        return false;
    });
});