ieViewMain.Proc.PreviewsParams := ieViewMain.Proc.PreviewsParams +
    [prppDefaultLockPreview];
  ieViewMain.Proc.DoPreviews([peHSL]);

procedure TMainForm.ImageEnView1ShowDialog(Sender: TObject; DlgType: TIEDlgType; Form: TForm);
begin
  // add Previews to uses
  if DlgType = iefProcPreview then
    with TfPreviews(Form) do
    begin
      ImageEn1.Visible := False;
      Label1.Visible := False;
      ResultToSourceButton.Visible := False;
      // And fix layout...
    end;
end;