John Singer Sarget is probably the best British/American portrait painter in history. He had a way with making fluid brushstrokes for clothing and then being very precise with faces, obviously the center of attention in a portrait (al last most of the time). This painting in particular is interesting because in the original version, the should strap on the dress was falling off her left shoulder. It was much too sexual for this woman who was the young wife of a rather old prominent member of high London society. So in order to fix the dress strap, Sargent had to make the left arm twist the strange way that it does.