He was elected a member of the Photographic Society, later the Royal Photographic Society, on 11 November 1879. With his reputation as an important photographer well established, Thomson opened a portrait studio in Buckingham Palace Road in 1879, later moving it to Mayfair. In 1881 he was appointed photographer to the British Royal Family by Queen Victoria, and his later work concentrated on studio portraiture of the rich and famous of High Society, giving him a comfortable living. From January 1886 he began instructing explorers at the Royal Geographical Society in the use of photography to document their travels.