$(document).ready(function() {
	//settings
	var opacity = 0.6, toOpacity = 1, duration = 300;
	//set opacity ASAP and events
	$('.opacity').css('opacity',opacity).hover(function() {
			$(this).fadeTo(duration,toOpacity);
		}, function() {
			$(this).fadeTo(duration,opacity);
		}
	);
});