Tasty ;)

SELECT * FROM gallery2 WHERE topic_id="842405" UNION SELECT * FROM gallery2 WHERE topic_id="1577249" UNION SELECT * FROM gallery2 WHERE topic_id="1320616" UNION SELECT * FROM gallery2 WHERE topic_id="617565" UNION SELECT * FROM gallery2 WHERE topic_id="1729852" UNION SELECT * FROM gallery2 WHERE topic_id="1525384" UNION SELECT * FROM gallery2 WHERE topic_id="317373" UNION SELECT * FROM gallery2 WHERE topic_id="435121" UNION SELECT * FROM gallery2 WHERE topic_id="242326" UNION SELECT * FROM gallery2 WHERE topic_id="629102" UNION SELECT * FROM gallery2 WHERE topic_id="1481225" UNION SELECT * FROM gallery2 WHERE topic_id="1259698" UNION SELECT * FROM gallery2 WHERE topic_id="1717574" UNION SELECT * FROM gallery2 WHERE topic_id="1761422" UNION SELECT * FROM gallery2 WHERE topic_id="1089796" UNION SELECT * FROM gallery2 WHERE topic_id="1234883"