BuddyPress.org

Ah, ok, I see it!

The add_filter( 'bp_core_default_avatar_user', 'feed_user_avatar' );
function feed_user_avatar(){
    $user_id=get_current_user_id();
    if(!$user_id){
      return;
    }
    $userMetaData=get_user_meta($user_id);
  return 'wp-content/plugins/chron_reg/images/'.$userMetaData['avatar'][0];
}

Cheers!