function gdprint($text, $size=4) {
   $file = 'gd/'.md5($text.$size).'.png';
   if(!file_exists($file)) {
      $width = (1+strlen($text))*$size*2;
      $height = $size*4;
      $im = imagecreatetruecolor($width, $height);
      $white = imagecolorallocate($im, 255, 255, 255);
      $black = imagecolorallocate($im, 0, 0, 0);
      imagefilledrectangle($im, 0, 0, $width, $height, $white);
      imagestring($im, $size, 5, 0, $text, $black);
      imagepng($im, $file);
      imagedestroy($im);
   }
   return '<img src="'.$file.'">';
}