Woocommerce List categories with Image thumbnail

Try this code:

    $taxonomyName = "product_cat";

    $parent_terms = get_terms($taxonomyName, array('parent' => 0, 'orderby' => 'slug', 'hide_empty' => false));

    echo '<ul>';
    foreach ($parent_terms as $pterm) {


        echo '<li><a href="' . get_term_link($pterm->name, $taxonomyName) . '">' . $pterm->name . '</a></li>';

        $thumbnail_id = get_woocommerce_term_meta($pterm->term_id, 'thumbnail_id', true);

        $image = wp_get_attachment_url($thumbnail_id);

        echo "<img src="{$image}" alt="" width="400" height="400" />";

        //Get the Child terms
        $terms = get_terms($taxonomyName, array('parent' => $pterm->term_id, 'orderby' => 'slug', 'hide_empty' => false));
        foreach ($terms as $term) {

            echo '<li><a href="' . get_term_link($term->name, $taxonomyName) . '">' . $term->name . '</a></li>';
            $thumbnail_id = get_woocommerce_term_meta($pterm->term_id, 'thumbnail_id', true);

            $image = wp_get_attachment_url($thumbnail_id);

            echo "<img src="{$image}" alt="" width="400" height="400" />";
        }
    }
    echo '</ul>';