Couldn't prepare mail with inline image using Thymeleaf templateEngine?

I am trying to send a html email with an inline-image attached using spring mvc and Thymeleaf. My code works without attaching the image. I get the html email successfully without image. But When I added the following line to my code I get the below error message.

Without this line code works and I get the email without image:

 message.addInline(image.getName(), imageSource,  image.getContentType());

This is the method:

public void sendUserRegisterEmail(String receiver, String receiverEmailAddress){
    MimeMessagePreparator preparator = new MimeMessagePreparator() {
        public void prepare(MimeMessage mimeMessage) throws Exception {

            Path path = Paths.get("/assets/dist/img/dialog_tv_logo-white-01.png");
            String fileName = "dialog_tv_logo-white-01.png";
            String originalFileName = "dialog_tv_logo-white-01.png";
            String contentType = "image/png";
            byte[] content = null;
            try {
                content = Files.readAllBytes(path);
            } catch (final IOException e) {
            }
            MultipartFile image = new MockMultipartFile(fileName,
                    originalFileName, contentType, content);

            Locale locale = Locale.getDefault();
            final Context ctx = new Context(locale);
            ctx.setVariable("name", receiver);
            ctx.setVariable("subscriptionDate", new Date());
            ctx.setVariable("imageResourceName", image.getName());

            MimeMessageHelper message = new MimeMessageHelper(mimeMessage);
            message.setSubject(USER_REGISTER_MESSAGE_SUBJECT);
            message.setTo(receiverEmailAddress);
            message.setFrom(SENDER_EMAIL_ADDRESS);
            final String htmlContent = emailTemplateEngine.process("email-inlineimage", ctx);
            message.setText(htmlContent, true /* isHtml */);

            final InputStreamSource imageSource = new ByteArrayResource(image.getBytes());
            message.addInline(image.getName(), imageSource,  image.getContentType());

           }
    };
    sendEmail(preparator);
}  

Following error message I get when the image prepare line is added:

 org.springframework.mail.MailPreparationException: Could not prepare mail; nested exception is java.lang.IllegalStateException: Not in multipart mode - create an appropriate MimeMessageHelper via a constructor that takes a 'multipart' flag if you need to set alternative texts or add inline elements or attachments.

Can any one figure out what is the issue here?

Finally able to fix the error after a lot of effort. Changing the following line fixed the issue. Create MimeMessageHelper by passing true

MimeMessageHelper message = new MimeMessageHelper(mimeMessage, true);