title: Ruby on Rails gmail does not display email images
body: <p>When my rails app sends email with image to gmail address - gmail does not display that image
  At the beginning I had image tag in my html email code:</p>
  
  <pre><code> &lt;img alt="" src="http://my_image/url/email_logo.svg" style="width: 200px; height: 40%;" /&gt;
  </code></pre>
  
  <p>But gmail does not display this image when I viewing it in the browser, but image displays if I viewing same email by using email client (AirMail)
  I changed this image to inline attachment:</p>
  
  <p>email view: </p>
  
  <pre><code>&lt;td valign="bottom"&gt;&lt;%= image_tag  attachments['email_logo.svg'].url , alt: '', style: "width: 200px; height: 40%;" -%&gt;&lt;/td&gt;
  </code></pre>
  
  <p>my_mailer.rb</p>
  
  <pre><code>def send_my_email(email)
      @email = email
      attachments.inline['email_logo.svg'] = File.read(Rails.root.join("app/assets/images/", "email_logo.svg"))
      mail(to: @email, subject: 'My Email')
    end
  </code></pre>
  
  <p>How to make gmail to display this image?  </p>