final public function resizeImage($width = null, $height = null)
	{
		if (is_int($width) and is_int($height)) {
			$new_image = imagecreatetruecolor($width, $height);
			imagecopyresampled(
				$new_image,
				$this->_image_handle,
				0,
				0,
				0,
				0,
				$width,
				$height,
				$this->imageWidth(),
				$this->imageHeight()
			);
			if (is_resource($new_image)) {
				$this->_image_handle = $new_image;
			}
		}
		return $this;
	}