php - cmb2 字段类型：文件未在前端显示图像？

Question

我添加了所有代码，后端没问题，但前端 img 源没有连接，前端没有显示图像。

短代码文件

add_shortcode('client-section','home_client_section_shortcode');

function home_client_section_shortcode($attr,$content){

     $client =  extract(shortcode_atts( array(
        'title'     => 'Oue Clients',
        'subtitle'  => 'Some of the best.'

      ), $attr) );

  ob_start(); ?>

    <section>
      <div class="container">
        <div class="title center">
          <h4 class="upper"><?php echo $subtitle; ?></h4>
          <h3><?php echo $title; ?><span class="red-dot"></span></h3>
          <hr>
        </div>
        <div class="section-content">
          <div class="boxes clients">

            <?php 

             $client = new WP_Query( array(
                'post_type'       => 'agro-client',
                'posts_per_page'  => 10

              ));

              $logo =  get_post_meta( get_the_id(),'_client-logo', true);

              while($client->have_posts()): $client->the_post(); 

               
              ?>
              

                 <div class="col-sm-4 col-xs-6 border-right border-bottom">

                  <img src="<?php echo wp_get_attachment_image($logo,'large'); ?>" alt="" data-animated="true" class="client-image">

                 </div>

              
            <?php endwhile; ?>

          </div>
        </div>
      </div>
    </section>

  <?php return ob_get_clean();
}

Cmb2 字段

// Home Client Section meta box

    $client= new_cmb2_box( array(
        'title'  => ' Client Logo Upload Fields',
        'id'     => 'client_fields',
        'object_types'  => array('agro-client')

    ));

    $client-> add_field( array(
        'name'  => 'Upload Client Logo',
        'id'    => '_client-logo',
        'type'  => 'file',
        'options' => array(
        'url' => false, // Hide the text input for the url
        ),
        'text'    => array(
        'add_upload_file_text' => 'Add or Upload Logo' // Change upload button text. Default: "Add or Upload File"
        ),


    ));

}

函数文件

// Custom post type Client 

    register_post_type('agro-client', array(
        'labels'    => array(
            'name'          => 'Client',
            'add_new'       => 'Add New Client',
            'add_new_item'  => 'Add New Client'
        ),
        'public'    => true,
        'supports'  => array('comments')

    ));