var set = 4;     
	var pic = new Array(set);  
        
	pic[0] = "images/160/image.160.1.jpg";
	pic[1] = "images/160/image.160.3.jpg";
	pic[2] = "images/160/image.160.4.jpg";
	pic[3] = "images/160/image.160.6.jpg";

	function select(range) {
	if (Math.random)
	return Math.round(Math.random() * (range-1));
	else {
	var now = new Date();
	return (now.getTime() / 1000) % range;
	} }

	var a = select(set);