Allen Snook

A WordPress plugin that gives users control over whether or not to opt-in to Gravatar. Avoids revealing Gravatars to logged-out visitors.

Profile Picture Privacy Controls

A WordPress plugin that gives users control over whether or not to opt-in to Gravatar. Avoids revealing Gravatars to logged-out visitors.

Venugopal

By default this plugin removes the comment date and gravatar. If you want to enable anything, go to this plugin settings and uncheck the checkbox.
More WordPress help please follow Me on this link 
<a href="https://venugopalphp.wordpress.com/" rel="nofollow ugc">Venugopal</a>

Comment Date and Gravatar remover

By default this plugin removes the comment date and gravatar. If you want to enable anything, go to this plugin settings and uncheck the checkbox.

Profile Picture Privacy Controls vs Comment Date and Gravatar remover