WooCommerce - Set product image to category image

<?php
  // WooCommerce - Set product image to category image
  remove_action( 'woocommerce_before_single_product_summary', 'woocommerce_show_product_images', 20 );
  add_action( 'woocommerce_before_single_product_summary', 'custom_show_product_images', 20 );
  function custom_show_product_images() {
    global $product;
    $product_id = $product->get_id();
    $cats = get_the_terms( $product_id, 'product_cat' );
    $cat = $cats[0]; // take the first category only
    $thumbnail_id = get_woocommerce_term_meta( $cat->term_id, 'thumbnail_id', true );
    $image = wp_get_attachment_url( $thumbnail_id );
    if ( $image ) {
      echo '<img src="'.$image.'" alt="'.$cat->name.'" />';
    }
  } // end function