title: Add cid image in thymeleaf template
body: <p>I have the following code :</p>
  
  <pre><code>Context context = getContext(transaction.getQuoteId(),transaction);
  body = templateEngine.process("....html", context);
  
  MimeMessage mail = javaMailSender.createMimeMessage();
  FileSystemResource logo = new FileSystemResource(new File("/images/logo.png"));
  MimeMessageHelper helper = new MimeMessageHelper(mail, true);
  helper.addInline("logo", logo);
  helper.setFrom(fromEmail);
  helper.setTo("...);
  helper.setSubject("....");
  helper.setText(body, true);
  javaMailSender.send(mail);
  </code></pre>
  
  <p>In html code I have:</p>
  
  <pre><code>&lt;td align="center" style="line-height: 0px; text-align:start;"&gt;
      &lt;img style="display:block; line-height:0px;margin-left: 30px;" src="cid:${logo}" width="200" alt="logo"&gt;
  &lt;/td&gt;
  </code></pre>
  
  <p>I also tried using <code>th:src="'cid:logo'"</code> but it didn't work. When I receive an email the image in not rendered.</p>
  
  <p>The image resides inside : </p>
  
  <pre><code>src/main/resources/images/logo.png
  </code></pre>
  
  <p>I also allowed access to "/images/.., /resources/.." in HttpSecurity ant matchers.</p>