function PopupImage(img){
  image1= new Image();
  image1.src=(img);
  Controlla(img);
}

function Controlla(img){
  if((image1.width!=0)&&(image1.height!=0)){
    viewImage(img);
  }
  else{
    funzione="Controlla('"+img+"')";
    intervallo=setTimeout(funzione,20);
  }
}

function viewImage(img){
  largh=image1.width+20;
  altez=image1.height+20;
  stringa="width="+largh+",height="+altez;
  finestra=window.open(img,"",stringa);
}