He is not just taller.

The animal is not a pony. It is a full-sized horse.

The young lady at right is known to me and I can verify her height at 5ft 4in.
The man to her left is the doctor.

Mr. Stadnyk, at left, has been documented in medical records, and on various dates, to have a height of 253-257 centimeters. The variation is attributed to several factors including time of day. The lowest number converts to just under 8 feet 4 inches.

The man in the middle is his doctor (I believe his name is Bessler), who is a tall man in his own right. He has, for a number of years, been studying and treating, patients with disorders leading to exceptional height.

The building in the background is Stadnyk's home, which was built by his family in a Ukrainian village. Since the home does not conform to standard construction practices, it should not be relied upon to provide scale.