var arr2 = new Image();
var arr1 = new Image();

arr2.src = "images/arrow2.gif";
arr1.src = "images/arrow.gif";

function PicOn(pic) 
{
	pic.parentNode.parentNode.firstChild.firstChild.src = arr2.src;
}

function PicOff(pic) 
{
	pic.parentNode.parentNode.firstChild.firstChild.src = arr1.src;
}