It took me a while to realize that CDV means carte de visite. I suggest that CdV would be a more appropriate abbreviation: it is not normal to capitalize particles.
I see that Queen Victoria's 4th child was Prince Alfred, Duke of Edinburgh and Admiral of the Fleet, who in 1874 married Marie Alexandrovna, only dau. of Tsar Aleksandr II. They had five children. Could she be the mother in the photo?