php 上传图片

public static function mkFolder($path)
{
if(!is_readable($path))
{
is_file($path) or mkdir($path);
}
}

public function Upload_上传图片()
{
$path = '/Upload/HuaHua/'.date("Ymd");
Lee::mkFolder($_SESSION["APP_ROOT"].$path);
$img = $_REQUEST['question_pic'];
$img = str_replace('data:image/jpeg;base64,', '', $img);
$img = str_replace(' ', '+', $img);
$data = base64_decode($img);
$file = $path .'/'.uniqid().'.jpeg';
$success = file_put_contents($_SESSION["APP_ROOT"].$file, $data);
if($success)
{
return  $_SESSION["STATIC_ROOT"].$file;
}
else
{
return null;
}
}