function Permut (flag,img) {
 if (document.images) {
  if (document.images[img].permloaded) {
   if (flag==1) document.images[img].src = document.images[img].perm.src
   else document.images[img].src = document.images[img].perm.oldsrc
  }
 }
}
function preloadPermut (img,adresse) {
 if (document.images) {
  img.onload = null;
  img.perm = new Image ();
  img.perm.oldsrc = img.src;
  img.perm.src = adresse;
  img.permloaded = true;
 }
}