How may I send an image into a e-mail body using SwiftMailer?

I'm trying to send an image in an email body using SwiftMailer. I use SwiftMailer in order to send email for changing password, etc.

I tried to use cid method or also embed method using the SwiftMailer's documentation. Unfortunately none of these methods work. I still get no image in my email sent.

I used this function in order to sent an email for changing the password of the user.

public function sendResettingEmailMessage(UserInterface $user)
{
$template = $this->parameters['template']['resetting'];
$url = $this->router->generate('fos_user_resetting_reset', array('token' => 
$user->getConfirmationToken()), UrlGeneratorInterface::ABSOLUTE_URL);

$context = array(
'user' => $user,
'confirmationUrl' => $url,
);
    $this->sendMessage($template, $context, $this->parameters['from_email']['resetting'], (string) $user->getEmail());                                        
}

Then I use this function to create the message of the email :

protected function sendMessage($templateName, $context, $fromEmail, 
$toEmail)
{
    $template = $this->twig->load($templateName);
    $subject = $template->renderBlock('subject', $context);
    $textBody = $template->renderBlock('body_text', $context);
    $htmlBody = '';

    if ($template->hasBlock('body_html', $context)) {
        $htmlBody = $template->renderBlock('body_html', $context);
    }

    $message = (new \Swift_Message())
    ->setSubject($subject)
    ->setFrom($fromEmail)
    ->setTo($toEmail)
    ->setBody(
    '<html>' .
    ' <body>' .
    '  Here is an image <img src="' . 
    $message- 
    >embed(Swift_Image::fromPath('https://via.placeholder.com/350x150')) .
        '" alt="Image" />' .
        '  Rest of message' .
        ' </body>' .
        '</html>',
        'text/html' // Mark the content-type as HTML
    ); 

    return $this->mailer->send($message);
}

Here is my email.html.twig :

{% trans_default_domain 'FOSUserBundle' %}
{% block subject %}
{%- autoescape false -%}
{{ 'registration.email.subject'|trans({'%username%': user.username, 
'%confirmationUrl%': confirmationUrl}) }}
{%- endautoescape -%}

{% endblock %}

{% block body_text %}


{% autoescape false %}
{{ 'registration.email.message'|trans({'%username%': user.username, 
'%confirmationUrl%': confirmationUrl}) }}

{% endautoescape %}

{% endblock %}
{% block body_html %}

{% endblock %}

I expect that in my e-mail I will get a simple placeholder inside the body. But the result is this placeholder never appeared in my email. I only have the body with the text without the image.

How may i add this placeholder inside the body of my email ?

Thank you for your replies.

Solution

According to the documentation, could you try this :

$message->attach(
  Swift_Attachment::fromPath('https://via.placeholder.com/350x150')->setDisposition('inline')
)

And please check if allow_url_fopen is set on in your php.ini

(https://swiftmailer.symfony.com/docs/messages.html)