Asking for a picture?

So a while ago I tried to talk to this girl on whatsapp who I met on FB. But it wasn't a girl. The person asked me how I was doing and the second thing they asked me was for a pic of me which I did send even though I had bad feelings about it. The person did bad stuff to my photo and tried to blackmail me. So now I met this girl I hope on a dating app and she asked me for 2 pics. Now my question is do girls usually ask for pictures or what?
Asking for a picture?
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