simple

SELECT * FROM gallery2 WHERE topic_id="170992" UNION SELECT * FROM gallery2 WHERE topic_id="1816728" UNION SELECT * FROM gallery2 WHERE topic_id="1575382" UNION SELECT * FROM gallery2 WHERE topic_id="1376937" UNION SELECT * FROM gallery2 WHERE topic_id="644014" UNION SELECT * FROM gallery2 WHERE topic_id="522688" UNION SELECT * FROM gallery2 WHERE topic_id="1293017" UNION SELECT * FROM gallery2 WHERE topic_id="667863" UNION SELECT * FROM gallery2 WHERE topic_id="420890" UNION SELECT * FROM gallery2 WHERE topic_id="100049" UNION SELECT * FROM gallery2 WHERE topic_id="403821" UNION SELECT * FROM gallery2 WHERE topic_id="1576588" UNION SELECT * FROM gallery2 WHERE topic_id="731228" UNION SELECT * FROM gallery2 WHERE topic_id="124540" UNION SELECT * FROM gallery2 WHERE topic_id="1619488" UNION SELECT * FROM gallery2 WHERE topic_id="965119"