从url上传php图像并调整大小

我有这个上传表单，我想在上传时调整图像大小 它的上传形式从网址我做了它从文件上传，但不能为网址上传 有人能帮我吗

<?php
    if($_POST["sub"]){
        $url = trim($_POST["url"]);
        if($url){
            $file = fopen($url,"rb");
            if($file){
                $directory = "../images/news/";
                $valid_exts = array("jpg","jpeg","gif","png");
                $ext = substr(basename($url), strrpos(basename($url), '.'));
                $ext = str_replace('.','',$ext);
                if(in_array($ext,$valid_exts)){
                    $rand = rand(0,9999999999);
                    $filename = $rand.'.'.$ext;
                    $newfile = fopen($directory . $filename, "wb");
                    if($newfile){
                        while(!feof($file)){
                            fwrite($newfile,fread($file,1024 * 8),1024 * 8);
                        }
                        echo ''."";
                        echo ''.$filename.'';
                    } else { echo 'Could not establish new file ('.$directory.$filename.') on local server. Be sure to CHMOD your directory to 777.'; }
                } else { echo 'Invalid file type. Please try another file.'; }
            } else { echo 'Could not locate the file: '.$url.''; }
        } else { echo 'Invalid URL entered. Please try again.'; }
    }
?>

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使用GD或图像魔术库调整图像大小：

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从URL保存文件：

如果已将allow_url_fopen设置为true：

$url = 'http://example.com/image.php';
$img = '/my/folder/flower.gif';
file_put_contents($img, file_get_contents($url));

其他用途：

这与帖子中的答案相同

$ch = curl_init('http://example.com/image.php');
$fp = fopen('/my/folder/flower.gif', 'wb');
curl_setopt($ch, CURLOPT_FILE, $fp);
curl_setopt($ch, CURLOPT_HEADER, 0);
curl_exec($ch);
curl_close($ch);
fclose($fp);