A man is looking at a photograph of someone. His friend asks who it is.
The man replies, 'Brothers and sisters, I have none. But that man's father is my father's son'.
Who is in the photograph?
Answer: The man's son.
A puzzle designed to make your brain twist. Break the puzzle into two sections:
A: that man's father
B: my father's son (which will be the man talking)
So by A, the father of the person in the photograph is (by B) the man talking.