Catherine Eliza Cobbe (1761–1839), the Honourable Mrs Henry Pelham Jean Laurent Mosnier (1743-1808)

The picture has something of this: people, portrait, wear, woman, dress, veil, queen, gown, princess, lid, wedding, model, jewelry, seat, opera, retro.
Perhaps it’s a painting of a woman in a white dress sitting on a red chair with a book in her lap and a hat on top of her head.