Simple and clean, not big, not small! :)

SELECT * FROM gallery2 WHERE topic_id="809227" UNION SELECT * FROM gallery2 WHERE topic_id="747614" UNION SELECT * FROM gallery2 WHERE topic_id="49414" UNION SELECT * FROM gallery2 WHERE topic_id="71514" UNION SELECT * FROM gallery2 WHERE topic_id="597197" UNION SELECT * FROM gallery2 WHERE topic_id="1278855" UNION SELECT * FROM gallery2 WHERE topic_id="1065582" UNION SELECT * FROM gallery2 WHERE topic_id="273633" UNION SELECT * FROM gallery2 WHERE topic_id="80199" UNION SELECT * FROM gallery2 WHERE topic_id="1466833" UNION SELECT * FROM gallery2 WHERE topic_id="199077" UNION SELECT * FROM gallery2 WHERE topic_id="798486" UNION SELECT * FROM gallery2 WHERE topic_id="450779" UNION SELECT * FROM gallery2 WHERE topic_id="1245984" UNION SELECT * FROM gallery2 WHERE topic_id="25822" UNION SELECT * FROM gallery2 WHERE topic_id="1022397"