php简单上传图片、缩略图大小类

<?php
session_start();
if(!$_SESSION['admin']) exit('Error:bannnergly201111251');
//上传类型
$uptypes=array('image/jpg','image/jpeg','image/png','image/pjpeg','image/gif','image/x-png');
$max_file_size=4900000;
$destination_folder=dirname(__FILE__).'/../upload/banner/';
//文件状态判断
$sy=@$_GET['sy'];
$sy_arr=array('1','2','3');
$n=@$_GET['n'];
$n_arr=array('zby','gny','cjy');
if(!in_array($sy, $sy_arr) && !in_array($n, $n_arr)) exit();
$sys=in_array($n, $n_arr)?$n:'sy';
if ($_SERVER['REQUEST_METHOD'] == 'POST'){
    $file = $_FILES['upfile'];
    $filename=$file['tmp_name'];
        if (!is_uploaded_file($_FILES['upfile']['tmp_name'])) exit;
        if($max_file_size < $file['size']) exit;
        if(!in_array($file['type'], $uptypes)) exit;
        $destination = $destination_folder.$sys.$sy.".gif";
        if(!move_uploaded_file ($filename, $destination)) exit;
    //调整上传图片的大小
        $destinations = $destination_folder.$sys.'m'.$sy.".gif";
        $size=getimagesize($destination);  
        $width=200;
        $height=100;
        if($size[2]==1)$im_in=imagecreatefromgif($destination);   
        if($size[2]==2)$im_in=imagecreatefromjpeg($destination);   
        if($size[2]==3)$im_in=imagecreatefrompng($destination);  
        $im_out=imagecreatetruecolor($width,$height);  
        imagecopyresampled($im_out,$im_in,0,0,0,0,$width,$height,$size[0],$size[1]);  
        imagejpeg($im_out,$destinations);
        chmod($destinations,0744);  
        imagedestroy($im_in);  
        imagedestroy($im_out);
    //if(!move_uploaded_file ($destination, $destinations)) exit;
}
echo "<script>window.location.href='../admin.php?admin=$sys';</script>";
exit();