This package used Facebook API to download friends' picture. Due to policy change, it can't be used anymore.
https://developers.facebook.com/docs/graph-api/changelog/breaking-changes/
4/4/2018
...
Returns Empty Set — The following nodes and edges will now only return empty data sets:
/achievement_id
/app/achievements
/app/scores
/user/achievements
/user/invitable_friends
/user/scores
/user/taggable_friends