low0 = new Image();
low0.src = "images/butt_low0.gif";
hi0 = new Image();
hi0.src = "images/butt_hi0.gif";
low1 = new Image();
low1.src = "images/butt_low1.gif";
hi1 = new Image();
hi1.src = "images/butt_hi1.gif";
low2 = new Image();
low2.src = "images/butt_low2.gif";
hi2 = new Image();
hi2.src = "images/butt_hi2.gif";
low3 = new Image();
low3.src = "images/butt_low3.gif";
hi3 = new Image();
hi3.src = "images/butt_hi3.gif";
low4 = new Image();
low4.src = "images/butt_language_low.jpg";
hi4 = new Image();
hi4.src = "images/butt_language_hi.jpg";
low5 = new Image();
low5.src = "images/butt_media_low.jpg";
hi5 = new Image();
hi5.src = "images/butt_media_hi.jpg";
low6 = new Image();
low6.src = "images/butt_method_low.jpg";
hi6 = new Image();
hi6.src = "images/butt_method_hi.jpg";

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