C# .NET高效压缩图片至1/10大小

//用法
        protected void Button1_Click(object sender, EventArgs e)
        {
            //上传控件获取二进制数
            byte[] path = FileUpload1.FileBytes;
            //二进制数转换Bitmap
            System.Drawing.Bitmap img = new System.Drawing.Bitmap((System.Drawing.Image)new System.Drawing.Bitmap(new MemoryStream(path)));
            //压缩图片
            byte[] by = ImageGdi(img);
            //转换成图片(图片大小仅为原图的1/10)
            System.Drawing.Image ys_img = System.Drawing.Image.FromStream(new MemoryStream(by));
        }


        ///
        /// GDI压缩图片
        ///
        /// 传入参数Bitmap
        ///
        public static byte[] ImageGdi(System.Drawing.Bitmap bmp)
        {
            System.Drawing.Bitmap xbmp = new System.Drawing.Bitmap(bmp);
            MemoryStream ms = new MemoryStream();
            xbmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            byte[] buffer;
            ms.Flush();
            if (ms.Length > 95000)
            {
                //buffer = ms.GetBuffer();
                double new_width = 0;