title: w3c markup validator ampersand (&) error
body: <p>Is there any workaround for the w3c validation error for an <code>&amp;</code> present in urls or some other place in HTML markup?<br>
  It says:  </p>
  
  <blockquote>
    <p>&amp; did not start a character reference. (&amp; probably should have been escaped as <code>&amp;amp;</code>.) </p>
  </blockquote>
  
  <p>The ampersand in my case is a part of a url for gravatar thumbnail. This is the problematic part of a url: </p>
  
  <blockquote>
    <p><code>c91588793296e2?s=50&amp;d=http%3A%2F%</code>.</p>
  </blockquote>