Lamprey, with His Owner Sir William Morgan, at Newmarket John Wootton (1682-1764)

The picture has something of this: cavalry, mammal, horse, seated, mare, two, people, racehorse, farm, equestrian, man, livestock, stallion, equine, animal, stable.
Perhaps it’s a painting of a man holding the reigns of a white horse with a group of men standing next to it in front of a red brick building.