Reid, Shoemakers.

I have in my possession a photograph of my great uncle Andrew Reid, born 1868, Kincardineshire.  We know for certain that it is him but I believe it is pasted on to a card by Cruickshank, photographers of Kemnay, and possibly had another photograph of Thomas Reid, son of Robert Reid, shoemaker of Kemnay.  On the back of the photo card is written "Thomas Reid, John's mother's father".  So I am not sure why Andrew Reid, who was originally a shoemaker, but joined the Metropolitan Police force in 1892, would have had this photograph at all as he lived and died in London whilst in the police force. Thomas Reid in the 1901 Kemnay census, was the son of Robert and Helen Reid(nee Archibald).  Can anyone shed some light on this please.