mj-carousel-align-border-radius-class.mjml

<mjml>
  <mj-body>
    <mj-section>
      <mj-column>
        <mj-carousel align="right" border-radius="2px" css-class="container">
          <mj-carousel-image alt="first" src="https://www.mailjet.com/wp-content/uploads/2016/11/ecommerce-guide.jpg" />
          <mj-carousel-image css-class="middle" src="https://www.mailjet.com/wp-content/uploads/2016/09/3@1x.png" />
          <mj-carousel-image href="https://jolimail.io" src="https://www.mailjet.com/wp-content/uploads/2016/09/1@1x.png" />
        </mj-carousel>
      </mj-column>
    </mj-section>
  </mj-body>
</mjml>