title: HTML email image tag missing src attribute
body: <p>I have a problem that I cant find the answer by Googling. I hope I can get one here.
  My problem is: My system can send email to user. On local, an image tag on email is like this:</p>
  
  <pre><code>&lt;img src="http://myimageurl" width="300" style="display:block;margin:auto" alt=""&gt;
  </code></pre>
  
  <p>When working on real server:</p>
  
  <pre><code>&lt;img width="300" style="display:block;margin:auto" alt=""&gt;
  </code></pre>
  
  <p>As you can see, my src attribute is disspeared. I just dont know why!</p>
  
  <p>My email tempalte(Im using cakePhp):</p>
  
  <pre><code>&lt;?php 
  echo $this-&gt;Html-&gt;image(
      Router::url('/', true). 'img/eventflair-logo.png',
          array(
              'width' =&gt; '300',
              'style' =&gt; 'display:block; margin: auto'
          )); 
  ?&gt;
  </code></pre>
  
  <p>Best Regards.</p>