I grow up in a clothed family to the point that taking off my shirt feels awkward. I never saw my parents naked but saw my siblings during our childhood days. Recently, we took a picture in a family outing and I smiled. My father pointed out that "hey, you smiled." in the picture while everyone in the picture didn't smile. I think smiling in pictures is not really a norm in the family.
On the other hand, I take off my shirt or even get naked when not in sight with my family.