You want to get the profile photo of a friend.
The profile address is
https://www.facebook.com/%5Busername%5D . Visit
User info in JSON
https://graph.facebook.com/%5Busername%5D . Here you’ll get the user ID too.
Tip from here.
If you want to check your privacy settings on Facebook, visit http://www.rabidgremlin.com/fbprivacy/.
“This page shows you what information the Facebook API provides to sites that you log into. It should highlight if you have left any of your personal information open for everyone to see.“
“This website provides an independent and open tool for scanning your Facebook privacy settings.“
Read more here.