function initHoverables(event) {
	$$('.hoverable').each(function(hoverable) {
		Event.observe(hoverable, 'mouseover', overHoverable, false);
		Event.observe(hoverable, 'mouseout', outHoverable, false);
	});
}
var hoverables = $H();
function overHoverable(event) {
	var img = Event.element(event);
	if (img.overImg == undefined) {
		var name = img.src.substring(0, img.src.lastIndexOf('.'));
		var ex = img.src.substring(name.length);
		img.overImg = new Image();
		img.overImg.src = name + '_over' + ex;
		img.outImg = new Image();
		img.outImg.src = img.src;
	}
	img.src = img.overImg.src;
}
function outHoverable(event) {
	var img = Event.element(event);
	img.src = img.outImg.src;
}
Event.observe(window, 'load', initHoverables, false);