A genetical phenomenon residing within a host. The host may be a person, place† or thing. Usually photogenetic qualities reside in people, or animals. This gene has an astounding ability to enhance its host's attributes in an event of a "photo opportunity". Said host gains a charismatic boost during a photographic moment. As noted before, this is a genetical phenomenon, meaning it is not directly passed down from one parent or the other; rather it is indirectly passed down from a member higher up the family tree. (usually several generations)
†In the case of a photogenic place, it is usually somewhere calm and peaceful; somewhere that when people see it, they are (more often than not) subconsciously pleased with the view. If in such a case that the person is consciously pleased with a view of the place, such place must be regarded as sacred; especially if viewed as such by a vast selection of people.
Did you see that picture of Britney falling down? Even in humiliation she still looked graceful!
Yea, man. She's really photogenic.