register_taxonomy_for_object_type('post_tag', 'attachment');
// optional:
// register_taxonomy_for_object_type('category', 'attachment');

Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/wp-content/uploads/code-snippets/518.php:1) in /var/www/html/wp-includes/sitemaps/class-wp-sitemaps-renderer.php on line 126
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="https://wdw.osfx.net/wp-sitemap-index.xsl" ?>
<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><sitemap><loc>https://wdw.osfx.net/wp-sitemap-posts-page-1.xml</loc></sitemap><sitemap><loc>https://wdw.osfx.net/wp-sitemap-posts-gd_place-1.xml</loc></sitemap><sitemap><loc>https://wdw.osfx.net/wp-sitemap-taxonomies-gd_placecategory-1.xml</loc></sitemap><sitemap><loc>https://wdw.osfx.net/wp-sitemap-users-1.xml</loc></sitemap></sitemapindex>