Image inside clonable group not displayed in template

Hello
I am trying to output following custom image fields inside a clonable group in my theme. I am using this code from your documentation. The text fields are displayed but not the image.

This are my custom fields:

add_filter( 'rwmb_meta_boxes', 'your_prefix_register_meta_boxes' );
function your_prefix_register_meta_boxes( $meta_boxes ) {
    $meta_boxes[] = array (
        'title' => 'Gallerie',
        'id' => 'gallerie',
        'post_types' => array(
            0 => 'exhibitions',
        ),
        'context' => 'normal',
        'priority' => 'high',
        'fields' => array(
            array (
                'id' => 'exhb_gallery_group',
                'type' => 'group',
                'name' => 'Bilder',
                'fields' => array(
                    array (
                        'id' => 'exhb_gallery',
                        'type' => 'single_image',
                        'name' => 'Einzelbild',
                    ),
                    array (
                        'id' => 'exhb_gallery_description',
                        'name' => 'Bildunterschrift',
                        'type' => 'wysiwyg',
                        'options' => array(
                            'textarea_rows' => 2,
                            'media_buttons' => false,
                            'teeny' => true,
                        ),
                    ),
                ),
                'clone' => 1,
                'sort_clone' => 1,
                'default_state' => 'expanded',
            ),
        ),
    );
    return $meta_boxes;
}

This is my template code:

// Group is cloneable
$group_values = rwmb_meta( 'exhb_gallery_group' );
    //print_r($group_values);
if ( ! empty( $group_values ) ) {
    foreach ( $group_values as $group_value ) {
        $image_ids = isset( $group_values['exhb_gallery'] ) ? $group_values['exhb_gallery'] : array();
        
        foreach ( $image_ids as $image_id ) {
            $image = RWMB_Image_Field::file_info( $image_id, array( 'size' => 'large' ) );
            echo '<img src="' . $image['url'] . '" width="' . $image['width'] . '" height="' . $image['height'] . '">';
            
            
        }
    
    echo '', $group_value['exhb_gallery_description'], '
';
    }
    
}

Thank you for your efforts!
Lukas