This looks like a still from Clark Gable's last movie "The Misfits". Co-starring Marilyn Monroe, her final completed film, Marilyn's character is appalled by the cruel method of breaking the wild horse.
These horses are known as "chocolate Palominos," and referred to as Taffys'. This one is a Taffy-Red color. No info on what breed of horse they are, if they are even the same. By size, I think they are.