Photo release?

That's a good question. I was recording in my smartphone, for fun, a kid throwing a grape up and catching it with his mouth, and the Children's pastor came over and was like, "Uuhmmm. . .No. No recording, no phone." very direct, but I immediately understood the concern and sorta said "duh!" to myself. Later she apologized for being so forward and blunt, but I told her I understood. She explained to me how some parents don't want pics of their kids taken, and stuff like that. But now you got me curious- we do definitely have some people who are the "official" picture takers, but I wonder how we get permission like this from all the parents and other concerned individuals. I'll have to ask, as I should know this as well!

yes you definitely need permission before you shoot, not after. So at all events and even regular sunday school you need a registration form that gives/revokes consent for photos to be taken and used with the strict intention of only supporting and promoting the church's ministry. Such photos should be taken on a specific camera ideally and a person assigned so the images don't end up sitting around in someone's house. Parents trust us with this kind of stuff, we need to take it very seriously and carefully work out a risk management strategy.
As for the 2 groups, unfortunately we do need to separate or 'stage' photos for promotional purposes if some children aren't allowed to be 'shot'. Otherwise you're going to end up with pixelated images or potentially angry parents.
Hope this helps