压缩远程图片并返回

   public ActionResult Pic()
        {
            var stram = new System.Net.WebClient().OpenRead("http://www.mj100.com/img/index/z_ban02.jpg");

            byte[] bytes=   MakeSmallImg(stram,500,500);

            return  File(bytes,"image/jpeg","1.jpg");
        }
        /// <summary>
        /// 压缩图片  15-5-4 by倩
        /// </summary>
        /// <param name="fromFileStream"></param>
        /// <param name="templateWidth"></param>
        /// <param name="templateHeight"></param>
        /// <returns></returns>
        public byte[] MakeSmallImg(System.IO.Stream fromFileStream, System.Double templateWidth, System.Double templateHeight)
        {
            //从文件取得图片对象，并使用流中嵌入的颜色管理信息
            System.Drawing.Image myImage = System.Drawing.Image.FromStream(fromFileStream, true);
            //缩略图宽、高
            System.Double newWidth = myImage.Width, newHeight = myImage.Height;
            //宽大于模版的横图
            if (myImage.Width > myImage.Height || myImage.Width == myImage.Height)
            {
                if (myImage.Width > templateWidth)
                {
                    //宽按模版，高按比例缩放
                    newWidth = templateWidth;
                    newHeight = myImage.Height * (newWidth / myImage.Width);
                }
            }
            //高大于模版的竖图
            else
            {
                if (myImage.Height > templateHeight)
                {
                    //高按模版，宽按比例缩放
                    newHeight = templateHeight;
                    newWidth = myImage.Width * (newHeight / myImage.Height);
                }
            }
            //取得图片大小
            System.Drawing.Size mySize = new Size((int)newWidth, (int)newHeight);
            //新建一个bmp图片
            System.Drawing.Image bitmap = new System.Drawing.Bitmap(mySize.Width, mySize.Height);
            //新建一个画板
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
            //清空一下画布
            g.Clear(Color.White);
            //在指定位置画图
            g.DrawImage(myImage, new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height),
            new System.Drawing.Rectangle(0, 0, myImage.Width, myImage.Height),
            System.Drawing.GraphicsUnit.Pixel);

            using (MemoryStream stream = new MemoryStream())
            {
                bitmap.Save(stream, ImageFormat.Jpeg);
                g.Dispose();
                myImage.Dispose();
                bitmap.Dispose();

                //输出字节流
                return stream.ToArray();

            }

        }