public static function delete_attachments( $post_id ) {
		// Is $post_id a vehicle?
		if ( self::POST_TYPE !== get_post_type( $post_id ) ) {
			// No, abort.
			return;
		}

		$attachments = get_posts(
			array(
				'post_parent'    => $post_id,
				'post_status'    => 'inherit',
				'post_type'      => 'attachment',
				'posts_per_page' => apply_filters( 'invp_query_limit', 1000, __METHOD__ ),
			)
		);

		foreach ( $attachments as $attachment ) {
			wp_delete_attachment( $attachment->ID );
		}

		// Delete the transients that hold this vehicle's photos.
		delete_transient( 'invp_get_the_photos_images_' . $post_id );
		delete_transient( 'invp_get_the_photos_image_urls_' . $post_id );
	}