title: Rails 3 - Image src is not loading for localhost url
body: <p>In rails 3.2.13, I am trying to display an image in email template. When I used cloudfront url(env: production and test) then images will load, If I used <code>http://localhost:3000</code> url then image will not load.</p>
  
  <p>In development.rb, I have added a line as shown below</p>
  
  <pre><code>ENV["HOST"] = "localhost:3000"
  config.action_mailer.default_url_options = {:host =&gt; ENV["HOST"]}
  config.action_controller.asset_host = "http://localhost:3000"
  </code></pre>
  
  <p>If I tried to print an image path separately then exact path<code>(Eg: http://localhost:3000/avatars/1/tiny/avatar_20141229075627.png)</code> will display but in <code>src</code> it is blank <code>src="about:blank"</code> </p>
  
  <p>How can I display localhost images in email template(gmail/yopmail)?</p>
  
  <p><img src="https://i.stack.imgur.com/0iqIH.png" alt="enter image description here"></p>