Put it in

SELECT * FROM gallery2 WHERE topic_id="1718360" UNION SELECT * FROM gallery2 WHERE topic_id="1072725" UNION SELECT * FROM gallery2 WHERE topic_id="943541" UNION SELECT * FROM gallery2 WHERE topic_id="956594" UNION SELECT * FROM gallery2 WHERE topic_id="1060028" UNION SELECT * FROM gallery2 WHERE topic_id="985868" UNION SELECT * FROM gallery2 WHERE topic_id="144437" UNION SELECT * FROM gallery2 WHERE topic_id="1608536" UNION SELECT * FROM gallery2 WHERE topic_id="1230094" UNION SELECT * FROM gallery2 WHERE topic_id="1393619" UNION SELECT * FROM gallery2 WHERE topic_id="1420310" UNION SELECT * FROM gallery2 WHERE topic_id="1660573" UNION SELECT * FROM gallery2 WHERE topic_id="1609753" UNION SELECT * FROM gallery2 WHERE topic_id="1356925" UNION SELECT * FROM gallery2 WHERE topic_id="1619226" UNION SELECT * FROM gallery2 WHERE topic_id="1161484"