Stop the thumbnails from generating?

How do you stop the 45×45 thumbnails from generating?

I just don’t need the extra image size as I don’t use it.

I know I can remove

/**
	 * Register new image size.
	 *
	 * @since  0.9.4
	 */
	function register_image_size() {
		add_image_size( 'rpwe-thumbnail', 45, 45, true );
	}

But I would have to edit it everytime there was an update.

https://ww.wp.xz.cn/plugins/recent-posts-widget-extended/