Close Front View: The gown is fastened in the front, which suggests that the back is one piece with no buttons. There are six buttons that are visible in the picture (maybe 1-3 got cut off?)
Front/Side View: You can see more of the front of the dress here.
Partial Back View: This was the best picture I could get of the back. You do get to see more of the shawl here, though!
Side View: In this picture, you can see that there is a transparent overlay to Georgiana's gown.