These images were used by Glasgow City Improvement Trust to document the overcrowded, unhygienic conditions ahead of extensive redevelopments.
These were eventually exhibited by Thomas' son, James Craig Annan, and reproduced in photogravure in Alfred Stieglitz's journal Camera Work.
Twenty years later, Annan's studio would be singled out by Baden Pritchard for its accomplishments in carbon printing and "beautiful pictures of exteriors and interiors of Scotch strongholds.
[12] James was a noted photogravurist and associated with late nineteenth-century art photography continued in his father's profession, receiving a Royal Warrant as 'Photographers and Photographic Engravers to Her Majesty in Glasgow'.
[14] The family business survives to the present day in the form of the Annan Fine Art Gallery, located on Woodlands Road in the West End of Glasgow.