function overImage(obj, baseName) {
	changeImage(obj, baseName+'_over.gif');
}
function outImage(obj, baseName) {
	changeImage(obj, baseName+'_normal.gif');
}
function changeImage(obj, url) {
	obj.src = url;
}

function changeBG(obj, url) {
	obj.style.background = "url('"+url+"')";
}