Unfortunately SamplesPerPixel and BitsPerSample properties are set just after AfterAcquireBitmap returns.
For this reason you may set these parameters manually, example:
procedure TForm1.ImageEnMView1MIOOnAfterAcquireBitmap(Sender:TObject; index:integer);
begin
case ImageEnMView1.ImageBitCount[index] of
1:
begin
ImageEnMView1.MIO.Params[index].BitsPerSample := 1;
ImageEnMView1.MIO.Params[index].SamplesPerPixel := 1;
end;
24:
begin
ImageEnMView1.MIO.Params[index].BitsPerSample := 8;
ImageEnMView1.MIO.Params[index].SamplesPerPixel := 3;
end;
end;
end;