// Create IEBitmap
Bmp := TIEBitmap.Create;

// Load monochrome bitmap with green and blue color and keep palette (don't convert to 24 bit)
Bmp.ParamsEnabled := true;
if Bmp.Params.Read('Bear_green_blue.bmp') then begin
   if (Bmp.Params.BitsPerSample * Bmp.Params.SamplesPerPixel <= 8) then begin
      Bmp.Params.NativePixelFormat := true;
   end;
end;
if Bmp.Read('Bear_green_blue.bmp') then ...

// Save bitmap as PNG
Bmp.ParamsEnabled := true;
Bmp.Params.NativePixelFormat := true;
if Bmp.Write('Bear_green_blue.bmp', ioPNG) then ... // the saved file uses black and white instead of green and blue

// Free IEBitmap
Bmp.Free;

ImageEnView1.IO.Params.NativePixelFormat := TRUE;
ImageEnView1.IO.LoadFromFile('D:\Bear_green_blue.bmp');

ImageEnView1.IO.Params.NativePixelFormat := FALSE;
ImageEnView1.IO.LoadFromFile('D:\Bear_green_blue.bmp');