Add featured image to feed

cmc-add-featured-image-to-feed.php

/*
 * Add featured image to feed
 */
add_filter( 'the_excerpt_rss', 'featuredToRSS' );
add_filter( 'the_content_feed', 'featuredToRSS' );
function featuredToRSS( $content ) {

	global $post;

	if ( has_post_thumbnail( $post->ID ) ) {
		$content = '<p>' . get_the_post_thumbnail( $post->ID, 'large-image', array( 'style' => 'margin:0; border: 10px solid #202020' ) ) . '</p>' . $content;
	}

	return $content;
}