WordPress 技巧：获取特色图片地址

<?php 
/*
Plugin Name: 获取 WordPress 特色图片地址
Plugin URI:  http://blog.wpjam.com/m/get_post_thumbnail_url/
Description: 获取 WordPress 特色图片地址。
Version: 0.1
Author: Denis
Author URI: http://blog.wpjam.com/
*/
function get_post_thumbnail_url($post_id){
	$post_id = ( null === $post_id ) ? get_the_ID() : $post_id;
	$thumbnail_id = get_post_thumbnail_id($post_id);
	if($thumbnail_id ){
		$thumb = wp_get_attachment_image_src($thumbnail_id, 'thumbnail');
		return $thumb[0];
	}else{
		return false;
	}
}

$post_thumbnail_url = get_post_thumbnail_url($post->ID);