This module integrates Drupal user pictures with the service provided by Gravatar. If the user has a gravatar linked with his or her e-mail address, it will be used as their user picture for comments, posts, and profile.
What is a Gravatar?
A gravatar, or globally recognized avatar, is quite simply an 80×80 pixel avatar image that follows you from weblog to weblog appearing beside your name when you comment on gravatar enabled sites. Avatars help identify your posts on web forums, so why not on weblogs?
Features
User roles can easily be assigned or denied permission to use Gravatars
Customizable picture size, maturity filter, and default pictures