Hjælp til resize af billede

<?php

if (phpversion() > "4.0.6") {
    $HTTP_POST_FILES = &$_FILES;
}
define("MAX_SIZE",300000);
define("DESTINATION_FOLDER", "billeder/1/");
define("no_error", "ok.php");
define("yes_error", "fejl.php");
$_accepted_extensions_ = "jpg,png,jpeg,gif";
if(strlen($_accepted_extensions_) > 0){
    $_accepted_extensions_ = @explode(",",$_accepted_extensions_);
} else {
    $_accepted_extensions_ = array();
}
$_file_ = $HTTP_POST_FILES['billede'];
if(is_uploaded_file($_file_['tmp_name']) && $HTTP_POST_FILES['billede']['error'] == 0){
    $errStr = "";
    $_name_ = $_file_['name'];
    $_type_ = $_file_['type'];
    $_tmp_name_ = $_file_['tmp_name'];
    $_size_ = $_file_['size'];
    $imginfo = getimagesize('billeder/1/'.$_name_.'');
        $imgwidth = $imginfo[0];  //bredde i pixels
        $imgheight = $imginfo[1]; //højde i pixels
   
    if($_size_ > MAX_SIZE && MAX_SIZE > 0){
        $errStr = "";
    }
    $_ext_ = explode(".", $_name_);
    $_ext_ = strtolower($_ext_[count($_ext_)-1]);
    if(!in_array($_ext_, $_accepted_extensions_) && count($_accepted_extensions_) > 0){
        $errStr = "";
    }
    if(!is_dir(DESTINATION_FOLDER) && is_writeable(DESTINATION_FOLDER)){
        $errStr = "";
    }
    if(empty($errStr)){
   
        if(@copy($_tmp_name_,DESTINATION_FOLDER . "/" . $_name_)){
            header("Location: " . no_error);

        } else {
            header("Location: " . yes_error);
        }
    } else {
        header("Location: " . yes_error);
    }
}
?>

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