GDI+ 操作TIFF ccitt t.6 压缩

Bitmap Bi=new Bitmap("C:\img.tif");
SaveFileDialog sfdlg = new SaveFileDialog();
sfdlg.Filter = "bmp文件(*.BMP)|*.BMP|All File(*.*)|*.*";
sfdlg.ShowDialog();
EncoderParameters eps = new EncoderParameters(1);
eps.Param[0] = new EncoderParameter(System.Drawing.Imaging.Encoder.Compression, (long)EncoderValue.CompressionCCITT4);
myImageCodecInfo = GetEncoderInfo("image/tiff");
Bi.Save(sfdlg.FileName, myImageCodecInfo, eps);