function daumenKino() {
    var $alt = $('#bilderstapel img.obersteebene');
    var $neu = $alt.next().length ? $alt.next() : $('#bilderstapel img:first');
    $alt.addClass('mittlereebene');
	$alt.removeClass('obersteebene');
    $neu.css({opacity: 0.0});
    $neu.addClass('obersteebene');
    $neu.animate({opacity: 1.0}, 2000, function() {
            $alt.removeClass('mittlereebene');
    });
}

$(document).ready(function() {
	setInterval( "daumenKino()", 6000 );
});