var showImg = function (url) {
 var frameid = 'frameimg' + Math.random();
 window.img = '<img id="img" src=\'' + url + '?' + Math.random() + '\' /><script>window.onload = function() { parent.document.getElementById(\'' + frameid + '\').height = document.getElementById(\'img\').height+\'px\'; }<' + '/script>';
 return '<iframe id="' + frameid + '" src="javascript:parent.img;" frameBorder="0" scrolling="no" width="100%"></iframe>';
}

<img class="form_logo" src="{:U('showMpImg')}?url={$vo.url}" style="max-width: none" width="160" height="100">

//顯示圖片
  public function showMpImg($url){
    header('content_type:image/jpeg');
    echo file_get_contents($url);
  }

$url = $request->input('url');
$ch = curl_init();
$httpheader = array(
 'Host' => 'mmbiz.qpic.cn',
 'Connection' => 'keep-alive',
 'Pragma' => 'no-cache',
 'Cache-Control' => 'no-cache',
 'Accept' => 'textml,application/xhtml+xml,application/xml;q=0.9,image/webp,/;q=0.8',
 'User-Agent' => 'Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2272.89 Safari/537.36',
 'Accept-Encoding' => 'gzip, deflate, sdch',
 'Accept-Language' => 'zh-CN,zh;q=0.8,en;q=0.6,zh-TW;q=0.4'
);
$options = array(
 CURLOPT_HTTPHEADER => $httpheader,
 CURLOPT_URL => $url,
 CURLOPT_TIMEOUT => 5,
 CURLOPT_FOLLOWLOCATION => 1,
 CURLOPT_RETURNTRANSFER => true
);
curl_setopt_array( $ch , $options );
$result = curl_exec( $ch );
curl_close($ch);
header('Content-type: image/jpg');
echo $result;
exit;