if (document.images) {
  fleche1on = new Image();
  fleche1on.src = "images/fleche-blanc-sur-gris.gif";

  fleche1off = new Image(17,16);
  fleche1off.src = "images/im-blanc.gif";

  fleche2on = new Image();
  fleche2on.src = "images/fleche-blanc-sur-gris.gif";

  fleche2off = new Image(17,16);
  fleche2off.src = "images/im-blanc.gif";
  
  fleche1bison = new Image();
  fleche1bison.src = "images/fleche-blanc-vert.gif";

  fleche1bisoff = new Image(17,16);
  fleche1bisoff.src = "images/im-blanc.gif";
  

  fleche3on = new Image();
  fleche3on.src = "images/fleche-blanc-sur-gris.gif";

  fleche3off = new Image(17,16);
  fleche3off.src = "images/im-blanc.gif";
}

function changeImages() {
  if (document.images) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src =  eval(changeImages.arguments[i+1] + ".src");
    }
  }
}