Painting of Sikhs in Hongkong in 1860's!

I have read a few articles on Sikhs in Thailand and Hongkong in 1800's and 1900's working as policemen, security guards, and soldiers. Here is an interesting picture of Sikh soldiers in Hongkong in 1860's. Check it out:

http://www.printsoldandrare.com/hongkong/021hong.jpg