function show_foto($image, $imgW, $imgH){
  var $img = new Image();
  $img.src = $image;
  
  var $left = (screen.width - $imgW) / 2;
  var $top = (screen.height - $imgH) / 2;
  
  window.open($image, '', 'menubar=no, toolbar=no, location=no, directories=no, status=no, scrollbars=no, resizable=no, left=' + $left + ', top=' + $top +', fullscreen=no, channelmode=no, width=' + $imgW + ', height=' + $imgH).focus();
  return false;
}