I always liked this painting hanging in the National gallery in London.
apparently Ingres was not keen on making portraits but when he met madame moitessier he quickly changed his mind. notice he even paints her twice in the same portrait.
I heard a story also that when he was painting the dress he couldn't get satisfied with it and repeatedly painted over and over untill he eventually broke down into tears, and madame moitessier got off her chair walked over to him and said " there, there, jean auguste dominique. be patient, dont worry, you will finish it" then he started again and painted it perfectly first time.