// 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":96,"count":1,"description":"","link":"https:\/\/riekoshimizu.com\/tag\/%e8%82%8c%e8%89%b2%e3%81%aa%e3%81%97\/","name":"\u808c\u8272\u306a\u3057","slug":"%e8%82%8c%e8%89%b2%e3%81%aa%e3%81%97","taxonomy":"post_tag","meta":[],"_links":{"self":[{"href":"https:\/\/riekoshimizu.com\/wp-json\/wp\/v2\/tags\/96"}],"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=96"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}