TBitmap загрузка изображения 256-цветнов (8-бит)

type
  TMyBitmap = class(TBitmap)
  public
    procedure Load256ColorBitmap(Instance: THandle; BitmapName: PChar);
  end;

procedure TMyBitmap.Load256ColorBitmap(Instance: THandle;
  BitmapName: PChar);
var
  HDib: THandle;
  Size: LongInt;
  Info: PBitmapInfo;
  FileHeader: TBitmapFileHeader;
  S: TMemoryStream;
begin
  HDib := LoadResource(Instance, FindResource(Instance, BitmapName,
    RT_BITMAP));
  if HDib <> 0 then
  begin
    Info := LockResource(HDib);
    Size := GetSelectorLimit(Seg(Info^)) + SizeOf(TBitmapFileHeader);
    with FileHeader do
    begin
      bfType := $4D42;
      bfSize := Size;
      bfReserved1 := 0;
      bfReserved2 := 0;
      bfOffBits := SizeOf(TBitmapFileHeader) + SizeOf(TBitmapInfoHeader);
      case Info^.bmiHeader.biBitCount of
        1: bfOffBits := bfOffBits + 2 * 4;
        4: bfOffBits := bfOffBits + 16 * 4;
        8: bfOffBits := bfOffBits + 256 * 4;
      end;
    end;
    S := TMemoryStream.Create;
    try
      S.SetSize(Size);
      S.Write(FileHeader, SizeOf(TBitmapFileHeader));
      S.Write(Info^, Size - SizeOf(TBitmapFileHeader));
      S.Position := 0;
      LoadFromStream(S);
    finally
      S.Free;
      FreeResource(HDib);
    end;
  end
  else
    raise EResNotFound.Create(Format('Не могу найти ресурс изображения %s',
      [BitmapName]));
end;

Image1.Picture.Bitmap := TMyBitmap.Create;
TMyBitmap(Image1.Picture.Bitmap).Load256ColorBitmap(hInstance, 'BITMAP_1');