This image previously appeared in Terry Bennett's "History of Photography in China: Western Photographers 1861–1879", published by Bernard Quaritch in 2010, with the caption:
Fig. 1.26. Hongkong Photographic Rooms. Reverse of fig. 1.25.
See http://gwulo.com/node/35363 for more information.
It is reproduced here with the permission of the author and publisher.