Is it wrong to post pictures of children that aren’t yours?

I don’t have children so I could be wrong but I just find it weird. I don’t think anyone should post pictures with children that aren’t their own. A lot of my friends have kids, and the friends that don’t help babysit the kids, myself included. I constantly see my other friends posting selfies with the babies and I just find it weird. It’s not group activity stuff. I might be overreacting. I find myself taking pictures too sometimes I just never post them. When the child does something cute or falls asleep I like to send the pictures to the mom. I’ll keep them because they make me happy but I don’t post them. I’m not judging anyone but I know for a fact they’ve never asked the mom and with all the craziness going around lately I wouldn’t want my baby being posted on social media.