This vintage postcard features a portrait of a father and his teenage daughter. Both are wearing wide brimmed hats. The daughter’s hat is a straw hat. She is holding gloves. It has occurred to me that this photograph may actually be showing a husband and his very young wife. The nature of their actual relationship will remain a mystery. The “AZO” stamp box reveals that this postcard portrait was taken sometime between 1904 and 1918.
THE CABINET CARD GALLERY 
He doesn’t seem to be wearing a wedding ring, so I think your first guess is correct. Their pose is ambiguous, but she looks a lot like him.