I don't give my picture to social media but in a way the fact that you have to take pictures directly from your app is the proper way to digitalised identifing someone. Back to the time where people phisically register, people will showed up to prove which face they have an match it with an non reproductible identity card. But, now I could easily inpersonnate 5 or 10 of my relative and love-ones from the picture I have from them and image of their id-card or another official document they have give me access to, or they have access from my computer once.