php脚本下载的图片打不开

<?php
/**
 * 抓取远程图片
 *
 * @param string $url 远程图片路径
 * @param string $filename 本地存储文件名
 */
function grabImage($url, $filename = '') {
    if($url == '') {
        return false; //如果 $url 为空则返回 false;
    }
    $ext_name = strrchr($url, '.'); //获取图片的扩展名
    if($ext_name != '.gif' && $ext_name != '.jpg' && $ext_name != '.bmp' && $ext_name != '.png') {
        return false; //格式不在允许的范围
    }
    if($filename == '') {
        $filename = time().$ext_name; //以时间戳另起名
    }
    //开始捕获
    ob_start();
    readfile($url);
    $img_data = ob_get_contents();
    ob_end_clean();
    $size = strlen($img_data);
    $local_file = fopen($filename , 'a');
    fwrite($local_file, $img_data);
    fclose($local_file);
    return $filename;
}
echo	grabImage("http://t1.baidu.com/it/u=1504295979,283866738&fm=52&gp=0.jpg");
?>

<?php
/**
 * 抓取远程图片
 *
 * @param string $url 远程图片路径
 * @param string $filename 本地存储文件名
 */
function grabImage($url, $filename = '') {
    if($url == '') {
        return false; //如果 $url 为空则返回 false;
    }
    $ext_name = strrchr($url, '.'); //获取图片的扩展名
    if($ext_name != '.gif' && $ext_name != '.jpg' && $ext_name != '.bmp' && $ext_name != '.png') {
        return false; //格式不在允许的范围
    }
    if($filename == '') {
        $filename = time().$ext_name; //以时间戳另起名
    }
    //开始捕获
    ob_start();
    readfile($url);
    $img_data = ob_get_contents();
    ob_end_clean();
    $size = strlen($img_data);
    $local_file = fopen($filename , 'a');
    fwrite($local_file, $img_data);
    fclose($local_file);
    return $filename;
}
echo	grabImage("http://t1.baidu.com/it/u=1504295979,283866738&fm=52&gp=0.jpg");
?>

function getImage($uri,$from){
ob_start();
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $uri);
if($from){
    curl_setopt($ch,CURLOPT_REFERER, $from);
}				
curl_exec($ch);
$img = ob_get_contents();
curl_close($ch);
ob_clean();
return $img;
}

$uri = "http://imgsrc.baidu.com/forum/pic/item/e55f70600c338744d0fbf8bd510fd9f9d62aa0b4.jpg";
$from = "http://tieba.baidu.com/i/28295132"; //这里请自行分析规律，一般情况分析HEADER中Referer

echo getImage($uri,$from);

$fs = fopen("abc.jpg","w+");
fwrite($fs,getImage($uri,$from));
fclose($fs);