/**
* [post_thumbnail_src 使用文章第一章图片作为缩略图,如果没，则随机输出1-9的JPG格式图片]
* @return [type] [description]
*/
function post_thumbnail_src(){
global $post;
if( $values = get_post_custom_values("thumb") ) { //输出自定义域图片地址
$values = get_post_custom_values("thumb");
$post_thumbnail_src = $values [0];
} elseif( has_post_thumbnail() ){ //如果有特色缩略图，则输出缩略图地址
$thumbnail_src = wp_get_attachment_image_src(get_post_thumbnail_id($post->ID),'full');
$post_thumbnail_src = $thumbnail_src [0];
} else {
$post_thumbnail_src = '';
ob_start();
ob_end_clean();
$output = preg_match_all('//i', $post->post_content, $matches);
$post_thumbnail_src = $matches [1] [0]; //获取该图片 src
if(empty($post_thumbnail_src)){ //如果日志中没有图片，则显示随机图片
$random = mt_rand(1, 10);
echo get_bloginfo('template_url');
echo '/images/pic/'.$random.'.jpg';
//如果日志中没有图片，则显示默认图片
//echo '/images/default_thumb.jpg';
}
};
echo $post_thumbnail_src;
}
