Trying

SELECT * FROM gallery2 WHERE topic_id="1755730" UNION SELECT * FROM gallery2 WHERE topic_id="234384" UNION SELECT * FROM gallery2 WHERE topic_id="38231" UNION SELECT * FROM gallery2 WHERE topic_id="816976" UNION SELECT * FROM gallery2 WHERE topic_id="787448" UNION SELECT * FROM gallery2 WHERE topic_id="824677" UNION SELECT * FROM gallery2 WHERE topic_id="1551354" UNION SELECT * FROM gallery2 WHERE topic_id="1254919" UNION SELECT * FROM gallery2 WHERE topic_id="685980" UNION SELECT * FROM gallery2 WHERE topic_id="1649096" UNION SELECT * FROM gallery2 WHERE topic_id="1687101" UNION SELECT * FROM gallery2 WHERE topic_id="1656098" UNION SELECT * FROM gallery2 WHERE topic_id="290518" UNION SELECT * FROM gallery2 WHERE topic_id="734825" UNION SELECT * FROM gallery2 WHERE topic_id="1071551" UNION SELECT * FROM gallery2 WHERE topic_id="1467469"