A fantastic picture! The lady wears a cape as it should be worn. It looks like a sea background and a lovely sunny day. This manifests itself in that the shadow of her hat and her right arm can be seen and obviously the sun is beaming down on her. The cape certainly has generous arm slits for going over a winter coat (the Queen, when Princess Elizabeth on the Royal tour of Canada wore a cape over her fur coat back in 1951). I get the impression that the lady is about to unbutton it any moment as her arms are reaching out. Just wish women still dressed like that on rainy days. The cape is not dissimilar to that pictured in 'Capes and Royalty'.
John