public function exists() {
		if ( null !== $this->exists ) {
			return $this->exists;
		}

		$thumbnail_id = get_post_thumbnail_id( $this->post_id );

		if ( empty( $thumbnail_id ) ) {
			$this->exists = false;
		} else {
			$this->thumbnail_id = $thumbnail_id;
			$this->exists       = true;
		}

		return $this->exists;
	}