Cacher is the code snippet organizer for pro developers

<?php
function get_thumbnail_url($post_id,$size) {
  if($size == ''){
    $size = 'full';
  }
  $thm_id = get_post_thumbnail_id($post_id);
  $url_data = wp_get_attachment_image_src($thm_id, $size);
  $return_data = array();
  $return_data['url'] = $url_data[0];
  $return_data['width'] = $url_data[1];
  $return_data['height'] = $url_data[2];
  return $return_data;
}