Link Feature Image to external url

Hi!

Well, I managed to link the Feature Image to it’s permalink with this code in functions php:

add_filter( 'post_thumbnail_html', 'my_post_image_html', 10, 3 );

function my_post_image_html( $html, $post_id, $post_image_id ) {

  $html = '<a href="' . get_permalink( $post_id ) . '" title="' . esc_attr( get_the_title( $post_id ) ) . '">' . $html . '</a>';
  return $html;

}

How should I modify it if I want to link the to an external url?

Thanks for your ideas!!

Carlos

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