Huge difference

SELECT * FROM gallery2 WHERE topic_id="953774" UNION SELECT * FROM gallery2 WHERE topic_id="1571637" UNION SELECT * FROM gallery2 WHERE topic_id="802456" UNION SELECT * FROM gallery2 WHERE topic_id="1268963" UNION SELECT * FROM gallery2 WHERE topic_id="4912" UNION SELECT * FROM gallery2 WHERE topic_id="85321" UNION SELECT * FROM gallery2 WHERE topic_id="1265706" UNION SELECT * FROM gallery2 WHERE topic_id="915607" UNION SELECT * FROM gallery2 WHERE topic_id="1729879" UNION SELECT * FROM gallery2 WHERE topic_id="144790" UNION SELECT * FROM gallery2 WHERE topic_id="1573500" UNION SELECT * FROM gallery2 WHERE topic_id="724309" UNION SELECT * FROM gallery2 WHERE topic_id="735577" UNION SELECT * FROM gallery2 WHERE topic_id="1232049" UNION SELECT * FROM gallery2 WHERE topic_id="1457856" UNION SELECT * FROM gallery2 WHERE topic_id="1496455"