function popup(w,h,site) { 
   x = screen.availWidth/2-w/2; 
   y = screen.availHeight/2-h/2; 
   popupWindow = window.open('js/pictureResized.php?path='+site,'','width='+w+',height='+h+',left='+x+',top='+y+',screenX='+x+',screenY='+y); 
}