PHP generates sample code to automatically create folders and upload files_PHP Tutorial

$uptypes=array('image/jpg','image/jpeg','image/png','image/pjpeg','image/gif','image/bmp','application/x-shockwave -flash','image/x-png');
$max_file_size=5000000; //Upload file size limit, unit BYTE

$addtime=date("Ymd",time());
$testdir="./".$addtime."/";
if(file_exists($testdir)):
else:
mkdir($testdir,0777);
endif;

$destination_folder=$addtime."/"; //Upload file path
$imgpreview=1; //Whether to generate a preview image (1 is generated, others are not generated);
$imgpreviewsize=1 /2; //Thumbnail ratio

if ($_SERVER['REQUEST_METHOD'] == 'POST')
{
if (!is_uploaded_file($_FILES["Pic"][tmp_name]))
//Whether the file exists
{
echo "File does not exist!";
exit;
}

$file = $_FILES["Pic"];
if($max_file_size < $file["size"])
//Check the file size
{
echo "< font color='red'>The file is too large! ";
exit;
}

if(!in_array($file["type"], $uptypes))
//Check file type
{
echo " can only be uploaded Image file or Flash! ";
exit;
}

if(!file_exists($destination_folder))
mkdir($destination_folder);

$filename=$file["tmp_name"];
$image_size = getimagesize($filename);
$pinfo=pathinfo($file["name"]);
$ftype=$ pinfo[extension];
$PicName = time().".".$ftype;
$destination = $destination_folder.$PicName;

if (file_exists($destination) && $overwrite != true)
{
echo "The file with the same name already exists!";
exit;
}