img=0;
 function img_rotate() {
  if ((++img)>4) img=0;
   switch (img) {
case 0:
  document.img.src = 'fotos/homebild1.jpg';
  break;
case 1:
  document.img.src = 'fotos/homebild2.jpg';
  break;
case 2:
  document.img.src = 'fotos/homebild3.jpg';
  break;
case 3:
  document.img.src = 'fotos/homebild4.jpg';
  break;
case 4:
  document.img.src = 'grafiken/banner/banner_senkrecht.gif';
  break;


       default:
        break;
   }
  window.setTimeout('img_rotate();',3500);
 }