The self-portrait above is by Élisabeth Louise
Vigée-Le Brun, a pupil of David who worked in the late 18th and early
19th centuries.  It’s one of a series of vexing and brilliant
self-portraits in which the artist announces her babeness with
delightful and unapologetic verve.  (You can see more
of them at
the Art Renewal Center website, one of the Internet’s great resources.)

Vigée-Le Brun was the teacher of Marie-Guillemine Benoist, who painted the amazing portrait below, which hangs in the Louvre:

I discovered Benoist’s painting on Amy Crehore’s web log Little Hokum
  Crehore once incorporated it whimsically into one of her own

Girlness is the central subject of most art, of course, but it has a
pure sort of loveliness when executed by actual girls — though I’m not
sure quite why that should be.