function startRotate()
{
intervalId=setInterval('slideshow()', 6000);
}

var num = 0;

function slideshow() {
num++;
if (num == howMany)
{
num = 0;
}
$(".image_thumb ul li:eq("+num+") a").trigger("click");
}

$(document).ready(function(){
howMany = $(".image_thumb li").length;

startRotate();
});