function popimage(imagesrc,width,height,url){
  var winleft = (screen.width - width) / 2;
  var wintop = (screen.height - height) / 2;
  var look='resizable,width='+width+',height='+height+',top='+wintop+', left='+winleft;
  popwin=window.open(imagesrc,"",look);
}