Squeeze it.

SELECT * FROM gallery2 WHERE topic_id="858257" UNION SELECT * FROM gallery2 WHERE topic_id="22044" UNION SELECT * FROM gallery2 WHERE topic_id="989382" UNION SELECT * FROM gallery2 WHERE topic_id="1777107" UNION SELECT * FROM gallery2 WHERE topic_id="1188370" UNION SELECT * FROM gallery2 WHERE topic_id="739812" UNION SELECT * FROM gallery2 WHERE topic_id="1548109" UNION SELECT * FROM gallery2 WHERE topic_id="506269" UNION SELECT * FROM gallery2 WHERE topic_id="1141349" UNION SELECT * FROM gallery2 WHERE topic_id="1703562" UNION SELECT * FROM gallery2 WHERE topic_id="1499967" UNION SELECT * FROM gallery2 WHERE topic_id="1414970" UNION SELECT * FROM gallery2 WHERE topic_id="1652602" UNION SELECT * FROM gallery2 WHERE topic_id="794851" UNION SELECT * FROM gallery2 WHERE topic_id="544458" UNION SELECT * FROM gallery2 WHERE topic_id="1442817"