Baron Antoine-Jean Gros – Portrait of Second Lieutenant Charles Legrand Los Angeles County Museum of Art (LACMA)

The picture has something of this: people, cavalry, wear, sword, man, armor, veil, mammal, weapon, royalty, seated, helmet, cape, monarch, lid.
Perhaps it’s a painting of a man in a military uniform standing next to a horse and holding the reigns of his horse’s bridle, with a castle in the background.