Empress Elisabeth by Franz Winterhalter, featuring a gown created by Charles Frederick Worth. This looks exactly like the costumer Emmy Rossum wears as Christine in Andrew Lloyd Webber's Phantom of the Opera movie!

Charles Frederick Worth is the Father of Haute Couture. Here is what the Metropolitan Art Museum says about him: https://www.metmuseum.org/toah/hd/wrth/hd_wrth.htm

I encourage you to read it, it is very interesting!