title: Angular Material, using mat-card-avatar without a card
body: <p>I just want to add a small round profile picture, I don't want it to be in a "card", and something like this actually works:</p>
  
  <pre><code>&lt;img mat-card-avatar src="avatar.png" alt="User Avatar"&gt;
  </code></pre>
  
  <p>That <code>&lt;img&gt;</code> is not contained in a <code>&lt;mat-card&gt;</code> element, and even though it works I'm wondering about the legality of the solution and possible side effects. So is it ok to use a mat-card-avatar like that outside of a mat-card element?  </p>
  
  <p>Also it took me a long time to find this directive, why was the avatar name-spaced as something that should be part of a card when it could generally be used in other contexts? For example I have it in a mat-toolbar.</p>