Squeeze them :)

SELECT * FROM gallery2 WHERE topic_id="756506" UNION SELECT * FROM gallery2 WHERE topic_id="35743" UNION SELECT * FROM gallery2 WHERE topic_id="1231893" UNION SELECT * FROM gallery2 WHERE topic_id="1768160" UNION SELECT * FROM gallery2 WHERE topic_id="923049" UNION SELECT * FROM gallery2 WHERE topic_id="1791246" UNION SELECT * FROM gallery2 WHERE topic_id="1015947" UNION SELECT * FROM gallery2 WHERE topic_id="1453080" UNION SELECT * FROM gallery2 WHERE topic_id="90422" UNION SELECT * FROM gallery2 WHERE topic_id="1044675" UNION SELECT * FROM gallery2 WHERE topic_id="784524" UNION SELECT * FROM gallery2 WHERE topic_id="560617" UNION SELECT * FROM gallery2 WHERE topic_id="1023048" UNION SELECT * FROM gallery2 WHERE topic_id="1680496" UNION SELECT * FROM gallery2 WHERE topic_id="1419732" UNION SELECT * FROM gallery2 WHERE topic_id="268950"