private static ImageCodecInfo GetEncoderInfo(String mimeType)

        {

            int j;

            ImageCodecInfo[] encoders;

            encoders = ImageCodecInfo.GetImageEncoders();

            for (j = ; j < encoders.Length; ++j)

            {

                if (encoders[j].MimeType == mimeType)

                    return encoders[j];

            }

            return null;

        }

        /// <summary>

        /// 图片压缩(降低质量以减小文件的大小)

        /// </summary>

        /// <param name="srcBitmap">传入的Bitmap对象</param>

        /// <param name="destStream">压缩后的Stream对象</param>

        /// <param name="level">压缩等级，0到100，0 最差质量，100 最佳</param>

        public static void Compress(Bitmap srcBitmap, Stream destStream, long level)

        {

            ImageCodecInfo myImageCodecInfo;

            Encoder myEncoder;

            EncoderParameter myEncoderParameter;

            EncoderParameters myEncoderParameters;

            // Get an ImageCodecInfo object that represents the JPEG codec.

            myImageCodecInfo = GetEncoderInfo("image/jpeg");

            // Create an Encoder object based on the GUID

            // for the Quality parameter category.

            myEncoder = Encoder.Quality;

            // Create an EncoderParameters object.

            // An EncoderParameters object has an array of EncoderParameter

            // objects. In this case, there is only one

            // EncoderParameter object in the array.

            myEncoderParameters = new EncoderParameters();

            // Save the bitmap as a JPEG file with 给定的 quality level

            myEncoderParameter = new EncoderParameter(myEncoder, level);

            myEncoderParameters.Param[] = myEncoderParameter;

            srcBitmap.Save(destStream, myImageCodecInfo, myEncoderParameters);

        }

        /// <summary>

        /// 图片压缩(降低质量以减小文件的大小)

        /// </summary>

        /// <param name="srcBitMap">传入的Bitmap对象</param>

        /// <param name="destFile">压缩后的图片保存路径</param>

        /// <param name="level">压缩等级，0到100，0 最差质量，100 最佳</param>

        public static void Compress(Bitmap srcBitMap, string destFile, long level)

        {

            Stream s = new FileStream(destFile, FileMode.Create);

            Compress(srcBitMap, s, level);

            s.Close();

        }