Legally speaking (at least in the U.S.), a "public figure" as a rule of thumb is anyone famous, whether or not they chose to be famous. This would include George, Blue Ivy Carter, North West, and any other famous baby. Their rights to privacy in a given situation, on the other hand, is another matter entirely. Is there a British definition to "public figure?"
I am under the impression that in Europe, the press can't take photos of a minor without the parent's permission. In the U.S., I believe this is different - if they can be seen from a public place, you can publish the photo (I think). I think Infanta Cristina learned this to her dismay when the family moved to Washington (before the Noos scandal was in the picture). I could be wrong about this -these are my general impressions on the subject.
Was this photo taken by paps or a member of the public, such as Instagram, etc? I am wondering if the privacy laws have kept up with the advent of social media, etc - where the public in effect has become a part of the press.
Is anybody aware of this, I am curious?