php-rss-bridge/bridges/MspabooruBridge.php

<?php

class MspabooruBridge extends GelbooruBridge {

	const MAINTAINER = 'mitsukarenai';
	const NAME = 'Mspabooru';
	const URI = 'https://mspabooru.com/';
	const DESCRIPTION = 'Returns images from given page';

	protected function buildThumbnailURI($element){
		return $this->getURI() . 'thumbnails/' . $element->directory
		. '/thumbnail_' . $element->image;
	}
}