website (dot) com/user_avatar/website/(username)/96/34_2.png is where its going to.
So on the main page for desktop it shows all the photos like here
On mobile it shows default avatars.
but when you go to the post thread it shows only default
unless a user reposts a new photo then it shows up.
Edit: my wife just told me more photos are visible from desktop then mobile. Not sure why.
@pfaffman this site is private for my wife and her friends but I can get you access if it helps.