Just the tip...

SELECT * FROM gallery2 WHERE topic_id="942028" UNION SELECT * FROM gallery2 WHERE topic_id="1555109" UNION SELECT * FROM gallery2 WHERE topic_id="516406" UNION SELECT * FROM gallery2 WHERE topic_id="506591" UNION SELECT * FROM gallery2 WHERE topic_id="1766971" UNION SELECT * FROM gallery2 WHERE topic_id="1048205" UNION SELECT * FROM gallery2 WHERE topic_id="879770" UNION SELECT * FROM gallery2 WHERE topic_id="1455557" UNION SELECT * FROM gallery2 WHERE topic_id="432860" UNION SELECT * FROM gallery2 WHERE topic_id="1428380" UNION SELECT * FROM gallery2 WHERE topic_id="796483" UNION SELECT * FROM gallery2 WHERE topic_id="1425638" UNION SELECT * FROM gallery2 WHERE topic_id="85751" UNION SELECT * FROM gallery2 WHERE topic_id="947277" UNION SELECT * FROM gallery2 WHERE topic_id="754377" UNION SELECT * FROM gallery2 WHERE topic_id="983567"