add_filter( 'related_posts_by_taxonomy_post_thumbnail_link', 'rpbt_related_post_meta_image', 10, 4 );

        function rpbt_related_post_meta_image( $image, $attr, $related, $args ) {

            $meta_image = get_field( 'dvd_cover' );

            if ( isset( $meta_image['url'] ) ) {
                $image = "<a href='{$attr['permalink']}' title='{$attr['title']}'><img src='{$meta_image['url']}'></a>";
            }

            return $image;
        }