// サムネにアイキャッチを使用
add_action( 'wp_head', 'add_meta_to_head' );
function add_meta_to_head() {
	echo '<meta name="thumbnail" content="' .wp_get_attachment_url( get_post_thumbnail_id() ). '" />';
}{"id":87,"count":2,"description":"","link":"https:\/\/riekoshimizu.com\/tag\/%e3%82%a4%e3%83%b3%e3%83%86%e3%83%aa%e3%82%a2\/","name":"\u30a4\u30f3\u30c6\u30ea\u30a2","slug":"%e3%82%a4%e3%83%b3%e3%83%86%e3%83%aa%e3%82%a2","taxonomy":"post_tag","meta":[],"_links":{"self":[{"href":"https:\/\/riekoshimizu.com\/wp-json\/wp\/v2\/tags\/87"}],"collection":[{"href":"https:\/\/riekoshimizu.com\/wp-json\/wp\/v2\/tags"}],"about":[{"href":"https:\/\/riekoshimizu.com\/wp-json\/wp\/v2\/taxonomies\/post_tag"}],"wp:post_type":[{"href":"https:\/\/riekoshimizu.com\/wp-json\/wp\/v2\/posts?tags=87"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}