WordPress，将值插入自定义帖子类型不起作用

处理表单时，我希望将值插入到自定义帖子类型products中。

这是我到目前为止所做的

 $art_title = $_POST['art_title'];
    $i = 0;
    foreach($art_title as $value) {
    $art_title = $_POST['art_title'][$i];
    $art_width = $_POST['art_width'][$i];
    $art_height = $_POST['art_height'][$i];
    $art_price = $_POST['art_price'][$i];
    $art_creation_date = $_POST['art_creation_date'][$i];
 $art_upload = $_FILE['art_upload'][$i];
       // Add the content of the form to $post as an array
        $new_post = array(
            'post_title'    => $art_title,
            'post_status'   => 'draft',    
            'post_type' => 'products'
        );
        //save the new post
        $pid = wp_insert_post($new_post); 
        $attachment_id = media_handle_upload( 'art_upload', $pid );
        if ( is_wp_error( $attachment_id ) ) {
            // There was an error uploading the image.
        } else {
            // The image was uploaded successfully!
        }
    $i++;
    }

我media_handle_upload和帖子 ID 一起使用，但这不起作用。

我想知道的是如何将这些 $_POST 值与图像一起插入自定义帖子类型products product_image？

自定义帖子类型是 wooCommerce products 。

任何帮助非常感谢。一个例子会很棒。