/**
  * Resize an image using the sfThubmnail Plugin.
  *
  * @param string $originalImageName
  * @param integer $width
  * @param integer $height
  *
  * @return string (thumbnail's bitstream)
  */
 public static function resizeImage($originalImageName, $width = null, $height = null)
 {
     $mimeType = QubitDigitalObject::deriveMimeType($originalImageName);
     // Get thumbnail adapter
     if (!($adapter = self::getThumbnailAdapter())) {
         return false;
     }
     // Check that this file can be thumbnailed, or return false
     if (self::canThumbnailMimeType($mimeType) == false) {
         return false;
     }
     // Create a thumbnail
     try {
         $newImage = new sfThumbnail($width, $height, true, false, 75, $adapter, array('extract' => 1));
         $newImage->loadFile($originalImageName);
     } catch (Exception $e) {
         return false;
     }
     return $newImage->toString('image/jpeg');
 }