function pickimage()
{
	var backgroundSrcs = new Array("pic_home.jpg", "pic_pub.jpg", "pic_teach.jpg", "pic_act.jpg", "pic_stu.jpg", "pic_schedule.jpg", "pic_contact.jpg");
	var bgimage=backgroundSrcs[(Math.floor(Math.random()*(backgroundSrcs.length)))];
	document.getElementById("pic").style.background="url("+bgimage+")";
	alret(bgimage);
}