The painting sold before Roxy's LaTour is Claude-Joseph Vernet's "La Nuit, au Port au Clair de Lune", which is in the Louvre's permanent collection.
This movie was originally set to star Winona Ryder and Natalie Portman, but both had to bow out before filming began. They appeared in Black Swan (2010) together.
When Isabel (Kate Hudson) is setting up chairs at the poetry reading and is confronted by Tellman (Matthew Modine), there are copies of "Le Divorce" by Diane Johnson on the bookshelf behind them.
The St. Ursula painting has a dominant female figure whose eyes are clearly looking to her left and her mouth is slightly tightened. At the end of this movie, sisters Roxeanne and Isabel get into a truck for their charity using the St. Ursula name and face as a large image on the back door of the truck. However, the St. Ursula image on the truck is looking straight ahead and with a slight smile. So it's not taken from the painting that has caused such turmoil in this movie.
The scene with the red purse bobbing in the wind is a reference or homage to iconic French short film, The Red Balloon (1956).