Social media

My husband and I have decided that we do not want pictures of our baby boy on social media when he is born. My family, as well as his, are very connected to their social media and I feel as though they wil get upset if we ask them not to post pictures of our baby. I feel bad because for his side of the family this is the first grandchild but we do not agree with the baby being on social media. We do not know the privacy settings of everyone and with ever changing settings people may not even know that their information is very public. How can I tell them this without upsetting them? I would have posted this... But I feel like it will not convey the message clearly enough and I don't want anything left up in the air.