The job of a parent is to protect their children from danger, but also to make a realistic assessment of risk and to avoid allowing unrealistic fears to dominate the child’s life, with a resulting negative impact on their opportunities, development and mental health.
this level of paranoia - especially about something like a photo which would not impact the child directly - is a really bad atmosphere to grow up in. The child will absorb your anxiety and think of themselves as being constantly unsafe.
far better to understand grooming - both of children and parents - and be alert to its signs, and to have strong enough boundaries to call it out within a family and friends setting.
You're assuming that parents sit down with their young children and tell young children that predators are everywhere and whip up paranoia.
Only speaking for myself, I certainly don't do that. Remaining clothed in the park is a rule, just like putting a helmet on at the skate park, or keeping their socks on in soft play.
I don't believe that saying to children "we wear swimwear or clothes at the splash pad" is going to make them anxious or paranoid. We don't go to the park naked, or the play area, and they see that most children are clothed. It's not an unusual thing to do.
To me it's much harder to teach children boundaries and how to protect themselves from grooming if the adults are sending messages like "pants area is private and if anyone wants to look there you must tell us" when at the weekend the same adult says "off you go, go run naked in front of all these people". It's mixed messages, is the pants area private or is it not? I never want my children to be in a position where an adult could manipulate them and their boundaries by taking advantage of their childhood brain saying things like "of course you can show me, you play at the beach/splash pad naked so it isn't that bad"