//extending jQuery with ':random' selector, best put into separate plugin js file
        jQuery.jQueryRandom = 0;
        jQuery.extend(jQuery.expr[":"],
        {
            random: function(a, i, m, r) {
                if (i == 0) {
                    jQuery.jQueryRandom = Math.floor(Math.random() * r.length);
                };
                return i == jQuery.jQueryRandom;
            }
        });        
        //end :random extend

        $(function() {
          $('#s_show img').not(':random').hide(); //hide all images except one initially
          setInterval(function(){
            $('#s_show img:visible').fadeOut('slow')
              .siblings('img:random').fadeIn('slow') //find a random image
               .end().appendTo('#s_show');}, 
            5000); //5 second interval
        });