Given the size of this horse, I'd have to guess that it was one of the working farm horses. Of course, it may not be as big as it appears - Aunt H. was only about five feet tall.
Bill was my grandmother's brother, William Hale Brubaker (1905-1979). Thag was my grandmother's first cousin, Thagrus Asher Burns (1917-2008). Aunt H. was my grandmother's aunt Hazlett (Wise) Burns (1885-1977). Date of photo unknown but Thag looks to be maybe 3-4 years old so it was probably taken about 1920-21.
Uncle Harl was Harlo Asher Burns (1880-1952). He was the husband of Hazlette Wise. I didn't know or remember him since I was only 4 years old when he passed away but according to my mother and her sisters, Uncle Harl was a rather large "somewhat uncouth" man but he loved his family - and his horses! Date of photo unknown.
Uncle Harl in the field with his horses. Date of photo unknown.