Pierre-Henri de Valenciennes – Study of Clouds over the Roman Campagna National Gallery of Art (Washington)

The picture has something of this: landscape, water, beach, sea, seashore, ocean, daylight, sky, storm, scenic, mountain, sunset, lake, light, weather, outdoors, desert, reflection.
Perhaps it’s a painting of a mountain scene with clouds in the sky and a man on a horse in the foreground with a dog.