[ WooCommerce ] Remove featured image/first image from product gallery

functions.php

<?php
// remove featured image from product gallery
add_filter('woocommerce_single_product_image_thumbnail_html', 'ds_remove_product_featured_image', 10, 2);
function ds_remove_product_featured_image($html, $attachment_id ) {
  global $post, $product;

  $featured_image = get_post_thumbnail_id( $post->ID );

  if ( $attachment_id == $featured_image )
    $html = '';

  return $html;
}

// remove first image from product gallery
add_filter( 'woocommerce_product_gallery_attachment_ids', 'ds_filter_product_gallery', 10, 2 );
function ds_filter_product_gallery( $ids, $product ){
    if (is_product()) {
        set_post_thumbnail( $post, $ids[0] );
        unset($ids[0]);
    }
    else {
        set_post_thumbnail( $post, end($ids));
    }
    return $ids;
}