I have a DS that goes to Y1 and I am in a group with 5 other mums from his class that our kids are good friends.
So, 6 mums in total in a what's app group.
In this group we talk about school news, parties etc. and we occasionally we send photos.
There is only one mum in this group that whenever she sends a photo that shows her kid, it disappears when you open it once. No other mum in the group does it and the photos she sends are harmless, like her kid on his new bike that he loves, or her kid climbing a wall while they were on holidays etc.
I am completely aware of the online risks and kids online safety, I don't have social accounts, I don't post my kid anywhere online. But honestly, in a group of 6 mums that you know well and meet everyday in school runs, who all have kids and are friends in the same class as your kid, do you need to send photos that disappear in 3 seconds? It's better not to send them at all...
AIBU - She is doing right and you need to do the same
AINBU - She is overreacting and this is too much