A Clydesdale Stallion John Frederick Herring (1795-1865)

The picture has something of this: cavalry, horse, mare, mammal, stallion, seated, equine, farm, animal, equestrian, mustang, pony, grass, racehorse, two, livestock, mane, agriculture, pasture.
Perhaps it’s a painting of a brown horse standing in a grassy field with a tree in the foreground and a blue sky in the background with white clouds.