WordPress - Remove the featured image from the content in feeds

wp-remove-featured-image.php

<?php
/**
 * Removes the "featured image" from the content
 * Google news stand/Facebook Instant Articles do not like it
 * Even different sizes of the Featured Image throw warnings
 * 
 * @param string $content The object/post content.
 */
function remove_featured_image_from_content( $content ) {
	// Get the post ID.
	$post_ID = get_the_ID();

	if ( has_post_thumbnail( $post_ID ) ) {

		// Get the featured image's data.
		$image_ID      = get_post_thumbnail_id( $post_ID );
		$image_info    = wp_get_attachment_metadata( $image_ID );
		$upload_dir    = wp_upload_dir();
		$upload_folder = $upload_dir['baseurl'];
		$image_date    = get_the_date( 'Y/m', $image_ID );

		// Check all the images of the post against the featured image and it's generated sizes.
		if ( isset( $image_info['sizes'] ) ) {

			foreach ( $image_info['sizes'] as $image_size ) {

				$file_name = $upload_folder . '/' . $image_date . '/' . $image_size['file'];
				$file_name = preg_quote( $file_name, '/' );

				// check if it's wrapped in a figure tag, then check for the image tag alone.
				$content = preg_replace( '/<figure.*?><img.*?src="(' . $file_name . ')".*?\>.*?<\/figure>/i', '', $content );
				$content = preg_replace( '/<img.*?src="(' . $file_name . ')".*?\>/i', '', $content );

				// remove any empty anchor links that might have been left behind.
				$content = preg_replace( '/<a[^>]*><\/a>/', '', $content );

			}
		}
	}

	return $content;
}
add_filter( 'the_content_feed', 'remove_featured_image_from_content' );