Henry Wright

This WordPress plugin will generate a default avatar for each user. Each default avatar is likely to be unique.
<h3>Requirements</h3>
You will need to compile PHP with the GD library for this plugin to work.

Default Avatars

Fun default avatars for your WordPress site.

shanebp

BP Local Avatars is a BuddyPress plugin.
Do you have members or groups on your BuddyPress site who do not have an Avatar? 
And you do not want to show the generic default avatar? 
Or maybe you do not want each page view to include a lot of calls to gravatar.com to load avatars?
<ul>
<li>This plugin will create a Gravatar Identicon avatar, thumb and full versions, for any user who does not already have an Avatar, and save it locally.</li>
<li>Supports user creation, user registration, user login, and Bulk Generation for user and groups.</li>
<li>Uses the existing BuddyPress avatar directory structure.</li>
<li>Conforms to the defined sizes for BuddyPress thumb and full avatars.</li>
<li>Users can still upload an avatar via their profile.</li>
<li>Groups can still upload an avatar via Group > Manage > Photo.</li>
</ul>
Usage:
<ol>
<li>
Provides an option in wp-admin under: 
Settings -> Discussion > Default Avatar > BuddyPress Identicon (Generated and Stored Locally).
</li>
<li>
Select and Save. Otherwise this plugin will not do anything.
</li>
<li>
After saving, you will see a link to ‘Bulk Generate’ avatars for all users and groups who do not have a local avatar. If a user already has their own Gravatar, it will save it locally.
</li>
</ol>
For more BuddyPress plugins, please visit <a href="https://www.philopress.com/" rel="nofollow ugc">PhiloPress</a>

BP Local Avatars

A BuddyPress plugin that creates Gravatar avatars for any user or group without one, and stores them locally.

Default Avatars vs BP Local Avatars