Signal, a Grey Arab, with a Groom in the Desert David Dalby of York (1794-1836)

The picture has something of this: cavalry, horse, mammal, seated, two, people, motion, equestrian, mare, equine, stallion, hurry, farm, action energy, racehorse, animal, veil, man.
Perhaps it’s a painting of a man leading a white horse in a desert with a tent in the background and a palm tree on the other side of the painting.