Saving CMYK Image in 400 DPI

public void SaveImage(String destimg, String destSmallImg, String destThumbImg)
            {
Aurigma.GraphicsMill.Codecs.JpegEncoderOptions EncoderOpt = new Aurigma.GraphicsMill.Codecs.JpegEncoderOptions();
EncoderOpt.Quality = 100;
                
                //-----------Convert into CMYK-------
                //bitmap = CManagment.ConvertToCMYK(bitmap);
                //------------------------------------

                //----------Saving in 400 DPI---------//
                bitmap.VerticalResolution = 400;
                bitmap.HorizontalResolution = 400;
                //----------Saving in 400 DPI---------//
                
                bitmap.Save(destimg, EncoderOpt);
                SaveThumbImage(destThumbImg, EncoderOpt);
                
   }