wpf 图片框image 显示byte[] 类型的图片

HttpItem item = new HttpItem();
HttpHelper http = new HttpHelper();
item.URL = "http://das.app.easypass.cn/Price/VerifyCode.aspx";
item.ResultType = ResultType.Byte;
HttpResult result = http.GetHtml(item);
// result.ResultByte;
BitmapImage bmi=new BitmapImage();
bmi.BeginInit();
MemoryStream ms=new MemoryStream(result.ResultByte);
bmi.StreamSource = ms;
bmi.EndInit();
img1.Source = bmi;