var myThumbs = document.getElementById('gallery_thumbs').getElementsByTagName('a');
for (var i=0; i<myThumbs.length; i++) {
	myThumbs[i].onclick = function() {swapImage(this)}
}
function swapImage(elemanchor) {
	for (var i=0;i<myThumbs.length;++i) {
		myThumbs[i].style.border = ''; // Neutral, invisible
	}
	myThumbs[0].style.border = '2px solid #fff';
	elemanchor.style.border = '2px solid #CC0033'; // Red
	// use the same image name as the thumbnail, but without "_th" at the end
	var mySrc = elemanchor.childNodes[0].src;
	mySrc = mySrc.substring(mySrc.lastIndexOf('/')+1, mySrc.lastIndexOf('_'));
	document.getElementById('photo_display').style.background = 'url(/images/' + mySrc + '.jpg) no-repeat';
}