Stream stream = null;
        StreamReader reader = null;
        MemoryStream ms = null;
        HttpWebResponse webResponse = null;
        try
        {
            WebRequest webRequest = HttpWebRequest.Create("http://image.sjq.cn/img/201002/99913/1213.jpg");   //打开图片地址
            webResponse = (HttpWebResponse)webRequest.GetResponse();
            stream = webResponse.GetResponseStream();
            reader = new StreamReader(stream);
            string textContent = reader.ReadToEnd();
            byte[] bytes = System.Text.Encoding.Default.GetBytes(textContent);
            ms = new MemoryStream(bytes);
            System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
             [color=#FF0000] ms参数无效[/color]
            //记录是否是图片个格式
            bool imgState = false;
            if (img.RawFormat == ImageFormat.Gif)
                imgState = true;
            if (img.RawFormat == ImageFormat.Jpeg)
                imgState = true;
            if (img.RawFormat == ImageFormat.Png)
                imgState = true;
            if (imgState)
            {
                imgHeight = img.Height;
                imgWidth = img.Width;
                imgSize = int.Parse(img.Size.ToString());
                md5 = getMd5Hash(textContent);
                if (ImagesManager.GetImgMarkIsExits(md5))
                {
                    message = "该图片已经存在!";
                    return false;
                }
                return true;
            }
            else
            {
                message = "该URL地址的目标不是图片";
                return false;
            }
        }
        catch (Exception ex)
        {
            message = ex.Message;
            message = "图片上传操作异常";
            return false;
        }
        finally
        {
            webResponse.Close();
            stream.Dispose();
            stream.Close();
            reader.Dispose();
            reader.Close();
            ms.Dispose();
            ms.Close();
        }