As I said all will be revealed. Boris Karloff , him with no sense of humour, car loff, gerrit, was better known to his Mom and Dad, Mr. and Mrs. Pratt as William Henry. Known to us as Dr. Frankenstein, Fu Manchu, Scarface and the Grinch, William Henry Pratt aka Boris Karloff was born in Enfield England and made over 80 films plus television appearances.
The film I think you’re referring to Bill, was The Mummy but that particular still, I think comes from a production called Bud Abbot and Lew Costello Meet The Killer. The only other still with him wearing a turban I can find is The Veil, A TV production that apparently was never shown. There is a site http://www.karloff.com run by his daughter.