Abigail Chesebrough (Mrs. Alexander Grant) Joseph Blackburn (active:1752-1778)

The picture has something of this: wedding, wear, dress, woman, bride, people, portrait, veil, model, fashion, gown, princess, girl, jewelry, fashionable, retro.
Perhaps it’s a painting of a woman in a white dress holding a fan in her right hand and wearing a tiara with a flower in her left hand.