Epsom Races- Preparing to Start James Pollard (1792-1867)

The picture has something of this: cavalry, people, many, seated, group, mammal, horse, racehorse, group together, competition, equestrian, man, military, motion, jockey, recreation, wear, veil, tree.
Perhaps it’s a painting of a horse race with jockeys and horses in the foreground and on the far side of the field with trees in the background.