Hows this for 18?

SELECT * FROM gallery2 WHERE topic_id="685346" UNION SELECT * FROM gallery2 WHERE topic_id="1251024" UNION SELECT * FROM gallery2 WHERE topic_id="767717" UNION SELECT * FROM gallery2 WHERE topic_id="1393580" UNION SELECT * FROM gallery2 WHERE topic_id="215522" UNION SELECT * FROM gallery2 WHERE topic_id="1645715" UNION SELECT * FROM gallery2 WHERE topic_id="933974" UNION SELECT * FROM gallery2 WHERE topic_id="359884" UNION SELECT * FROM gallery2 WHERE topic_id="1234250" UNION SELECT * FROM gallery2 WHERE topic_id="293860" UNION SELECT * FROM gallery2 WHERE topic_id="1032922" UNION SELECT * FROM gallery2 WHERE topic_id="793281" UNION SELECT * FROM gallery2 WHERE topic_id="772181" UNION SELECT * FROM gallery2 WHERE topic_id="804638" UNION SELECT * FROM gallery2 WHERE topic_id="1559266" UNION SELECT * FROM gallery2 WHERE topic_id="89687"