function preload(){
 this.length=preload.arguments.length;
 for (var i=0; i<this.length; i++){
  this[i]=new Image();
  this[i].src=preload.arguments[i];}}

imgs=new preload(
"i/ljubljana2005.jpg",
"i/paris2005.jpg");

function on(PicName){
 document['thumb'].src='i/'+PicName+'.jpg';
}
function off(PicName){
 document['thumb'].src='i/blank.gif';
}