mdiamondstone

authorGrid is a sidebar widget that displays the avatar of any author on your blog with at least one published post in grid form. You 
can set how large the avatar should be, how many columns (or rows) you’d like in the grid, and the display title of the widget.

Author Grid

Sidebar widget that displays the avatar of all of the authors on your blog in grid form.

SuitePlugins

BuddyPress Private Avatar gives users an extra sense of security by allowing them to hide their profile picture from guests and members that are not friends of the user.
BP Private Avatar is perfect for all social network sites built using BuddyPress. It works great for the following types of social networks; Education, Health Community, Business, Dating and so much more.
Users simply go to the Profile Settings and choose ‘Make Profile Photo Private’ to hide the Avatar.
Looking for more BuddyPress plugins?
<a href="https://suiteplugins.com/plugins//?utm_source=wordpress&utm_medium=plugin&utm_content=bp-private-avatar" rel="nofollow ugc">SuitePlugins</a> 
<a href="https://profiles.wordpress.org/suiteplugins/" rel="nofollow ugc">SuitePlugins Repo</a>

Private Avatars for BuddyPress

BP Private Avatars allows users to hide the avatar to only friend connections for additional privacy.

Author Grid vs Private Avatars for BuddyPress