Finally useful…

SELECT * FROM gallery2 WHERE topic_id="646778" UNION SELECT * FROM gallery2 WHERE topic_id="1113584" UNION SELECT * FROM gallery2 WHERE topic_id="1419981" UNION SELECT * FROM gallery2 WHERE topic_id="1477959" UNION SELECT * FROM gallery2 WHERE topic_id="544112" UNION SELECT * FROM gallery2 WHERE topic_id="714352" UNION SELECT * FROM gallery2 WHERE topic_id="421674" UNION SELECT * FROM gallery2 WHERE topic_id="189108" UNION SELECT * FROM gallery2 WHERE topic_id="976988" UNION SELECT * FROM gallery2 WHERE topic_id="448591" UNION SELECT * FROM gallery2 WHERE topic_id="285972" UNION SELECT * FROM gallery2 WHERE topic_id="1109866" UNION SELECT * FROM gallery2 WHERE topic_id="475636" UNION SELECT * FROM gallery2 WHERE topic_id="100719" UNION SELECT * FROM gallery2 WHERE topic_id="189351" UNION SELECT * FROM gallery2 WHERE topic_id="1213735"