function Bildwechsel (Bildnr, Bildobjekt) {
  window.document.images[Bildnr].src = Bildobjekt.src;
}

Normal1 = new Image();
Normal1.src = "img/nav_01_0.gif";    
Highlight1 = new Image();
Highlight1.src = "img/nav_01_1.gif"; 

Normal2 = new Image();
Normal2.src = "img/nav_02_0.gif";     
Highlight2 = new Image();
Highlight2.src = "img/nav_02_1.gif"; 


Normal3 = new Image();
Normal3.src = "img/nav_03_0.gif";    
Highlight3 = new Image();
Highlight3.src = "img/nav_03_1.gif";