about.html: Add the size of the gravatar image we currently use.

docs/about.html

@@ -30,7 +30,7 @@ lead: "Learn about the project's history, meet the maintaining teams, and find o
       <div class="list-group-item">
         <iframe class="github-btn" src="http://ghbtns.com/github-btn.html?user={{ member.user }}&amp;type=follow"></iframe>
         <a class="team-member" href="https://github.com/{{ member.user }}">
-          <img src="http://www.gravatar.com/avatar/{{ member.gravatar }}" alt="@{{ member.user }}" width="32" height="32">
+          <img src="http://www.gravatar.com/avatar/{{ member.gravatar }}.jpg?s=32" alt="@{{ member.user }} avatar" width="32" height="32">
           <strong>{{ member.name }}</strong> <small>@{{ member.user }}</small>
         </a>
       </div>
@@ -44,7 +44,7 @@ lead: "Learn about the project's history, meet the maintaining teams, and find o
       <div class="list-group-item">
         <iframe class="github-btn" src="http://ghbtns.com/github-btn.html?user={{ member.user }}&amp;type=follow"></iframe>
         <a class="team-member" href="https://github.com/{{ member.user }}">
-          <img src="http://www.gravatar.com/avatar/{{ member.gravatar }}" alt="@{{ member.user }}">
+          <img src="http://www.gravatar.com/avatar/{{ member.gravatar }}.jpg?s=32" alt="@{{ member.user }} avatar" width="32" height="32">
           <strong>{{ member.name }}</strong> <small>@{{ member.user }}</small>
         </a>
       </div>