$(

function() {

	$(".slideshow img:first").addClass("slideshow_on").css( {opacity: 1.0} );
    setInterval(
		function slideSwitch() {
			var $on = $(".slideshow_on");
			var $next =  $on.next().length ? $on.next() : $(".slideshow img:first");
			$on.css( {opacity: 1.0} ).removeClass("slideshow_on").animate( {opacity: 0.0} , 2000, function() { } );
			$next.css( {opacity: 0.0} ).addClass("slideshow_on").animate( {opacity: 1.0} , 2000, function() { } );
		}
		, 4000
	);

}

);