I think I might be able to help with this one, John Cameron is also my Great, Great Grandfather as per the attached tree.
I am not aware of John Cameron as having traveled to Hong Kong, but his son (My Great Grandfather, William Ramsay Cameron) trained as a ships engineer and traveled to Hong Kong around the turn of the century.
Family folklore has it that that William Ramsay Cameron traveled to China with the Ben Line, based in Leith around the turn of the century. He somehow missed his ship back home and ended up in Hong Kong holding a senior position in the just built Hong Kong harbour.
I can speak to my father, who can recall many of William Ramsay Cameron's stories - But I believe that your pictures may well be of him. If you have any scans or any other details of him, I'd be extremely grateful to receive it and fill in this piece of family history myself... I've always been fascinated by his story.
Alistair Cameron