This photo is known to have been taken by Brady. However it is on a Carte de visite of George G. Rockwood of 839 Broadway. Rockwood opened his studio in New York in 1857. He was famous for his carte de visite photos. His photos are well known and quite special.
However how did a Brady photo get on his label? Maybe Brady was broke and sold the negative of Irving? I guess more investigation is due, but it sure is an interesting mystery. I would guess that this photo as it is was made by Rockwood in the 1860's. It does mention on the back of the photo that it is a copy and not direct from life. But why was it copied? That is the mystery?