public function get_extension(){
    parent::get_extension();
		if ( !$this->ext2 && $this->file ){
			if ( function_exists('exif_imagetype') ){
				if ( $r = exif_imagetype($this->file) ){
          if ( !array_key_exists($r, bbn\file\image::$allowed_extensions) ){
            $this->ext = false;
          }
				}
				else{
          $this->ext = false;
        }
			}
			if ( $this->ext ){
				$this->ext2 = $this->ext;
				if ( $this->ext2 === 'jpg' ){
          $this->ext2 = 'jpeg';
        }
			}
		}
		return $this->ext;
	}