var imgover="start";
function highlight(imgname)
{
	myImage = new Image();
	myImage.src ="images/portfolio/" + imgname + "_thumbOn.jpg";
	document.getElementById(imgname).src = myImage.src;
}

function nohighlight(imgname)
{
	myImage = new Image();
	myImage.src ="images/portfolio/" + imgname + "_thumb.jpg";
	document.getElementById(imgname).src = myImage.src;
}

function changepic(imgname)
{
	if (imgover != imgname && imgover !="start")
	{
	    nohighlight(imgover);
	}
	imgover = imgname;
	highlight(imgname);	
}