/// <summary>

        /// 压缩图片

        /// </summary>

        /// <param name="iSource">图片文件</param>

        /// <param name="outPath">路径</param> 例如 var outPath = Path.Combine(Request.MapPath("~/Upload"), Path.GetFileName(file.FileName));

        /// <param name="flag">值越大代表图片质量越好，一般默认控制在50为最佳压缩质量</param>

        /// <returns></returns>

        public static bool ReduceImage(Image iSource, string outPath, int flag)

        {

            ImageFormat tFormat = iSource.RawFormat;

            EncoderParameters ep = new EncoderParameters();

            long[] qy = new long[1];

            qy[0] = flag;

            EncoderParameter eParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qy);

            ep.Param[0] = eParam;

            try

            {

                ImageCodecInfo[] arrayICI = ImageCodecInfo.GetImageDecoders();

                ImageCodecInfo jpegICIinfo = null;

                for (int x = 0; x < arrayICI.Length; x++)

                {

                    if (arrayICI[x].FormatDescription.Equals("JPEG"))

                    {

                        jpegICIinfo = arrayICI[x];

                        break;

                    }

                }

                if (jpegICIinfo != null)

                    iSource.Save(outPath, jpegICIinfo, ep);

                else

                    iSource.Save(outPath, tFormat);

                return true;

            }

            catch

            {

                return false;

            }

            finally

            {

                iSource.Dispose();

            }

        }

 /// <summary>

        ///byte[] 图片转换

        /// </summary>

        /// <param name="buffer"></param>

        /// <returns></returns>

        public static Image BytesToImage(byte[] buffer)

        {

            MemoryStream ms = new MemoryStream(buffer);

            Image image = System.Drawing.Image.FromStream(ms);

            return image;

        }

  /// <summary>

        /// 使用流方式,上传并保存文件

        /// </summary>

        /// <param name="s">文件流</param>

        /// <param name="savepath">保存文件路径</param>

        /// <param name="warning">处理警告信息,若为空,则处理成功</param>

        /// <returns>返回文件保存完整路径</returns>

        public static string uploadbystream(Stream s, string savepathFolder, out string warning)

        {

            try

            {

                int be = 0;

                if (s.Length > 0)

                {

                    MemoryStream ms = new MemoryStream();

                    while ((be = s.ReadByte()) != -1)

                    {

                        ms.WriteByte((byte)be);

                    }

                    string reletiveFolder = "UploadFile\\ManageImage\\" + savepathFolder + "\\" + DateTime.Now.Year + "\\" + DateTime.Now.Month;

                    string folderPath = HttpContext.Current.Server.MapPath("~/") + reletiveFolder;

                    if (!Directory.Exists(folderPath))

                        Directory.CreateDirectory(folderPath);

                    string filename = DateTime.Now.ToString("yyyyMMddHHmmss") + ".jpg";

                    string newpath = folderPath + "\\" + filename;

                    string lastpath = "";

                    lastpath = newpath;

                    //FileExistMapPath(newpath, FileCheckModel.M, out lastpath);

                    FileStream fs = new FileStream(lastpath, FileMode.Create);

                    ms.WriteTo(fs);

                    //释放

                    ms.Dispose();

                    fs.Dispose();

                    warning = "";

                    return reletiveFolder + "\\" + filename;

                }

                warning = "error";

                return "";

            }

            catch (Exception ex)

            {

                warning = "error" + ex.Message;

                return "";

            }

        }