Event.observe(window, 'load', init_gallery)

function init_gallery() {
	$$('#content div.gallery a.thumbnail').each(function(a){
		a.observe('mouseover', thumbnailize.bindAsEventListener(a));
		a.observe('click', function(e){ Event.stop(e); });
	});
}

function thumbnailize(e) {
	document.getElementsByClassName('placeholder', this.parentNode)[0].src = this;
	Event.stop(e);
}