procedure TForm1.Button1Click(Sender: TObject);
var
  MyImage : TImageEnView;
  FileName : string;
  Is24RGB : boolean;
  I: Integer;
begin
  FileName := 'D:\Save.PDF';

  if FileExists(FileName) then
    DeleteFile(PChar(FileName));

  MyImage := TImageEnView.Create(nil);
  MyImage.LegacyBitmap := False;
  try
    MyImage.IO.CreatePDFFile(FileName);
    try
      for I := 0 to Listbox1.Items.Count - 1 do
      begin
        MyImage.IO.LoadFromFileTIFF(Listbox1.Items[i]);

        MyImage.IO.Params.PDF_PaperWidth  := MyImage.IEBitmap.Width;
        MyImage.IO.Params.PDF_PaperHeight := MyImage.IEBitmap.Height;

        if chkForceMono.checked then
        begin
          MyImage.Proc.ConvertToBWThreshold(-1);
          MyImage.RemoveAlphaChannel();
        end;

        Is24RGB := MyImage.IEBitmap.PixelFormat = ie24RGB;

        if Is24RGB then
          MyImage.IO.Params.PDF_Compression := ioPDF_JPEG
        else
          MyImage.IO.Params.PDF_Compression := ioPDF_G4FAX;

        MyImage.IO.SaveToPDF;
      end;

    finally
      MyImage.IO.ClosePDFFile;
    end;
  finally
    MyImage.Free;
  end;
end;