php写一个函数,实现扫描并打印出自定目录下(含子目录)所有jpg文件名

<?php

$dir = "E:\照片\\";

//打印文件夹中所有jpg文件
function printJpg($dir,$deep = ""){
 $dirSource = dir($dir);

 while($d = $dirSource->read()){
  if($d == "." || $d == ".."){
   continue;
  }
  if(filetype($dir.$d) == "dir"){
   printJpg($dir.$d."/",$deep."--");
  }

  if(mime_content_type($dir.$d) == "image/jpeg"){

   echo $deep.$d."<br/>";
  }
 }
}

printJpg($dir);