procedure TForm1.ImageEnMView1DblClick(Sender: TObject);
var
  i: Integer;
begin
  if (ImageEnMView1.DisplayMode = mdGrid) then
  begin
    i := ImageEnMView1.SelectedImage;
    ImageEnMView1.DisplayMode := mdSingle;
    ImageEnMView1.ThumbWidth := ImageEnMView1.Width;
    ImageEnMView1.ThumbHeight := ImageEnMView1.Height;
    {Specifies the visible image when TImageEnMView.DisplayMode is
    mdSingle or TImageEnMView.Playing is True.}
    ImageEnMView1.VisibleFrame := i;
  end
  else
  begin
    i := ImageEnMView1.VisibleFrame;
    ImageEnMView1.DisplayMode := mdGrid;
    ImageEnMView1.ThumbWidth := TrackBar1.Position;
    ImageEnMView1.ThumbHeight := TrackBar1.Position;
    ImageEnMView1.SelectedImageAlwaysVisible := True;
    ImageEnMView1.SelectedImage := i;
  end;
end;