title: In C#, how can I parse out a url from a html page that I have got using webproxy.load()?
body: <p>I am trying to read in the current day's dilbert image. I am able to get the full text of the page by doing this:</p>
  
  <pre><code>        var todayDate = DateTime.Now.ToString("yyyy-MM-dd");
              var web = new HtmlWeb();
              web.UseCookies = true;
              var wp = new WebProxy("http://myproxy:8080");
              wp.UseDefaultCredentials = true;
              NetworkCredential nc = (NetworkCredential)CredentialCache.DefaultCredentials;
              HtmlDocument document = web.Load("http://www.dilbert.com/strips/comic/" + todayDate, "GET", wp, nc);
  </code></pre>
  
  <p>if I look at the full html of the document I see the <a href="http://assets.amuniversal.com/c2168fa0c45a0132d8f0005056a9545d" rel="nofollow">image</a> listed multiple times on the page such as:</p>
  
  <pre><code>&lt;meta property="og:image" content="http://assets.amuniversal.com/c2168fa0c45a0132d8f0005056a9545d"/&gt;
  </code></pre>
  
  <p>or:</p>
  
  <pre><code>&lt;meta name="twitter:image" content="http://assets.amuniversal.com/c2168fa0c45a0132d8f0005056a9545d"&gt;
  </code></pre>
  
  <p>or</p>
  
  <pre><code>  &lt;img alt="Squirrel In The Large Hadron Collider - Dilbert by Scott Adams" class="img-responsive img-comic" height="280" src="http://assets.amuniversal.com/c2168fa0c45a0132d8f0005056a9545d" width="900" /&gt;
  </code></pre>
  
  <p>what is the best way to parse out the URl from this picture?</p>