Just worked out

SELECT * FROM gallery2 WHERE topic_id="621839" UNION SELECT * FROM gallery2 WHERE topic_id="69075" UNION SELECT * FROM gallery2 WHERE topic_id="667804" UNION SELECT * FROM gallery2 WHERE topic_id="413627" UNION SELECT * FROM gallery2 WHERE topic_id="1421083" UNION SELECT * FROM gallery2 WHERE topic_id="1314705" UNION SELECT * FROM gallery2 WHERE topic_id="1598321" UNION SELECT * FROM gallery2 WHERE topic_id="1659804" UNION SELECT * FROM gallery2 WHERE topic_id="1048434" UNION SELECT * FROM gallery2 WHERE topic_id="773337" UNION SELECT * FROM gallery2 WHERE topic_id="363687" UNION SELECT * FROM gallery2 WHERE topic_id="99090" UNION SELECT * FROM gallery2 WHERE topic_id="55007" UNION SELECT * FROM gallery2 WHERE topic_id="1628749" UNION SELECT * FROM gallery2 WHERE topic_id="469207" UNION SELECT * FROM gallery2 WHERE topic_id="1453632"