WordPress Version: 5.1
/**
* Removes the thumbnail (featured image) from the given post.
*
* @since 3.3.0
*
* @param int|WP_Post $post Post ID or post object from which the thumbnail should be removed.
* @return bool True on success, false on failure.
*/
function delete_post_thumbnail($post)
{
$post = get_post($post);
if ($post) {
return delete_post_meta($post->ID, '_thumbnail_id');
}
return false;
}