Menu image and subtitle

menu-image-subtitle.php

<?php
// simple function to insert post meta 
// subtitle and menu_image 
// in to sub menu items of primary navigation

function db_menu_insert_post_meta($sorted_menu_objects, $args) {
    // select the menu
    if ($args->theme_location === 'primary'){
        // get the menu objects
        foreach ($sorted_menu_objects as $menu_object) {
            // get any posttype menu item that are not parents
            if ( in_array($menu_object->object, array('post', 'page', 'any_post_type')) 
                && $menu_object->menu_item_parent != 0 
            ) {
                // get the custom content 
                $subtitle = get_post_meta($menu_object->object_id, 'subtitle', true);
                $menu_image = get_post_meta($menu_object->object_id, 'menu_image', true);
                $thumbnail = wp_get_attachment_image($menu_image, 'thumbnail', false, array( 'class' => 'menu-thumbnail' ));
                // build the custom classes and menu item
                if ($subtitle || $thumbnail){
                    $menu_object->classes[] = 'custom-menu';
                    if ($subtitle){$menu_object->classes[] = 'has-subtitle';}
                    if ($thumbnail){$menu_object->classes[] = 'has-thumbnail';}
                    $menu_object->title = sprintf(
                        '%1$s %2$s %3$s',
                        $thumbnail,
                        '<span class="menu-item-label">'.$menu_object->title.'</span>',
                        $subtitle ? '<span class="menu-subtitle">' . $subtitle . '</span>' : ''      
                    );
                }
            }
        }
    }
    return $sorted_menu_objects;
}
add_filter('wp_nav_menu_objects', 'db_menu_insert_post_meta', 10, 2);

// basic CSS Styling
.main-nav ul li.custom-menu a {
    display: flex;
    flex-direction: column;
    flex-wrap: wrap;
    max-height: 60px;
    align-content: flex-start;
    justify-content: center;
}
.menu-thumbnail {
    width: 36px;
    border-radius: 100%;
    margin-right: 10px;
}