Let me check for existing research to ensure the title isn't too similar. Quick search... Seems like most titles focus on broader FKK aspects, so a specific focus on children's imagery could be a niche angle.
I think the best titles would combine the cultural context, the focus on children, and either the historical, ethical, sociological, or psychological perspective. Let me list a few options and pick the most balanced one. Fkk Kinder Bilder
If you are looking for artistic or historical representations of the FKK movement that include family life, you can explore: Let me check for existing research to ensure