An interesting portrait, she looks like she's a subject of a Louis XVI era painting by Vigee LeBrun. Bright and smiling young woman with an overall blue palette. The frame is actually a large brooch mount, ornate bow top, a thick plating of 14k gold. Full measurements noted on the photos.
Very good to excellent, age and type considered. I feel certain this would have been a 19th century painting made for the Grand Tour tourist souvenir trade. Likely Victorian era. Nicely made and a very appealing portrait.