On WhatsApp there is a function that turns ordinary photos into "stickers". For example, a picture of a baby in the park can be cut out so that all the background is removed and it's just the picture of the baby itself on its own. It can then be used like you would use emojis.
My younger sister (35 y/o - age given to help with context ie. she is not so young that she won't understand why I'm unhappy about it) has been making about 10 different ones all of my DC who is nearly a year old. Then she uses them instead of 😭😩😂 etc. in all sorts of group chats. I believe most are with family and probably none with people I don't already know. I have now heard some of my cousins also use these stickers who I see maybe 4 or 5 times a year if that. But I just feel uncomfortable about it. AIBU to want her to stop?
I feel like we live in an age where we can't control who has photos of our children. I use Facebook and Instagram (albeit not often) but have chosen not to post any photos of my DC there, and generally don't have many photos of myself or DH there either