{
        /// <summary>
        /// 对上传的图片进行等比缩放
        /// </summary>
        /// http://www.cnblogs.com/babycool
        /// <param name="fromFile">获取文件流Stream</param>
        /// <param name="fileSaveUrl">缩略图保存完整路径</param>
        /// <param name="targetWidth">模板宽度</param>
        /// <param name="targetHeight">模板高度</param>
        public static void ZoomPic(System.IO.Stream fromFile, string fileSaveUrl, System.Double targetWidth, System.Double targetHeight)
        {
            //原始图片（获取原始图片创建对象，并使用流中嵌入的颜色管理信息）
            System.Drawing.Image initImage = System.Drawing.Image.FromStream(fromFile, true);
            //原图宽高均小于模版，不作处理，直接保存
            if (initImage.Width <= targetWidth && initImage.Height <= targetHeight)
            {
                //保存
                initImage.Save(fileSaveUrl, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            else
            {
                //缩略图宽、高计算
                double newWidth = initImage.Width;
                double newHeight = initImage.Height;
              //宽大于高或宽等于高（横图或正方）
                if (initImage.Width > initImage.Height || initImage.Width == initImage.Height)
                {
                    //如果宽大于模版
                    if (initImage.Width > targetWidth)
                    {
                        //宽按模版，高按比例缩放
                        newWidth = targetWidth;
                        newHeight = initImage.Height * (targetWidth / initImage.Width);
                    }
                }
                //高大于宽（竖图）
                else
                {
                    //如果高大于模版
                    if (initImage.Height > targetHeight)
                    {
                        //高按模版，宽按比例缩放
                        newHeight = targetHeight;
                        newWidth = initImage.Width * (targetHeight / initImage.Height);
                    }
                }

                //生成新图
                //新建一个bmp图片
                System.Drawing.Image newImage = new System.Drawing.Bitmap((int)newWidth, (int)newHeight);
                //新建一个画板
                System.Drawing.Graphics newG = System.Drawing.Graphics.FromImage(newImage);
                //设置质量
                newG.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                newG.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

                //置背景色
                newG.Clear(Color.White);
                //画图
                newG.DrawImage(initImage, new System.Drawing.Rectangle(0, 0, newImage.Width, newImage.Height), new System.Drawing.Rectangle(0, 0, initImage.Width, initImage.Height), System.Drawing.GraphicsUnit.Pixel);

                //保存缩略图
                newImage.Save(fileSaveUrl, System.Drawing.Imaging.ImageFormat.Jpeg);
                //释放资源
                newG.Dispose();
                newImage.Dispose();
                initImage.Dispose();
            }
            
        }
    }