Just a little off the top ;)

SELECT * FROM gallery2 WHERE topic_id="564204" UNION SELECT * FROM gallery2 WHERE topic_id="1250158" UNION SELECT * FROM gallery2 WHERE topic_id="1676974" UNION SELECT * FROM gallery2 WHERE topic_id="533643" UNION SELECT * FROM gallery2 WHERE topic_id="660340" UNION SELECT * FROM gallery2 WHERE topic_id="1344180" UNION SELECT * FROM gallery2 WHERE topic_id="722201" UNION SELECT * FROM gallery2 WHERE topic_id="578455" UNION SELECT * FROM gallery2 WHERE topic_id="562598" UNION SELECT * FROM gallery2 WHERE topic_id="919247" UNION SELECT * FROM gallery2 WHERE topic_id="1679951" UNION SELECT * FROM gallery2 WHERE topic_id="1206172" UNION SELECT * FROM gallery2 WHERE topic_id="1206837" UNION SELECT * FROM gallery2 WHERE topic_id="793353" UNION SELECT * FROM gallery2 WHERE topic_id="1557786" UNION SELECT * FROM gallery2 WHERE topic_id="1249863"