window.addEvent('domready', function(){
	var img_opacity = {
		'mousedown': function(){
			this.setStyle('opacity', .5);
		},
		'mouseup': function(){
			this.setStyle('opacity', 1);
		},
		'mouseleave': function(){
			this.setStyle('opacity', 1);
		}
	};
	
	$$('a').each(function(el){
		var img = el.getElement('img');
		if (!img ) return;
		el.addEvents(img_opacity);
	});
	
	$$('input[type=image]').each(function(el){
		el.addEvents(img_opacity);
	});
});