压缩图片

    Bitmap bitmap = (Bitmap) Image.FromFile(@"e:\3.jpg ");
    ImageCodecInfo encoder = null;
    foreach (ImageCodecInfo info2 in ImageCodecInfo.GetImageEncoders())
    {
        if (info2.MimeType == "image/jpeg")
        {
            encoder = info2;
        }
    }
    EncoderParameters encoderParams = new EncoderParameters();
    encoderParams.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, (long)16);
    bitmap.Save(@"e:\bak.jpg", encoder, encoderParams);