Adicionar imagem de destaque do WP no RSS/Feed

functions.php

//Adiciona Imagem de Destaque no feed RSS
	function featuredtoRSS($content) {
		global $post;
		if (has_post_thumbnail($post->ID)){
			$content = '<div>'.get_the_post_thumbnail($post->ID, 'medium', array('style'=>'margin-bottom:15px;')).'</div>'.$content;
		}
		return $content;
	}
	add_filter('the_excerpt_rss', 'featuredtoRSS');
	add_filter('the_content_feed', 'featuredtoRSS');