function daumenKino() {
    var $alt = $('#banner_blanko img.obersteebene');
    
      var $neu = $alt.next().length ? $alt.next() : $('#banner_blanko img:first');
    $alt.addClass('mittlereebene');
   $alt.removeClass('obersteebene');
    $neu.css({opacity: 0.0});
    $neu.addClass('obersteebene');
    $neu.animate({opacity: 1.0}, 3000, function() {
            $alt.removeClass('mittlereebene');
    });
}
$(document).ready(function() {
  var length = $('.sss').length;
    if (length > 1 ) {
     setInterval( "daumenKino()", 4500 ); 
   }
});