procedure TForm1.tmrUpdatePreviewTimer(Sender: TObject);
var
  iMaxX: Integer;
  iMaxY: Integer;
  iCanStretch: Boolean;
  iQualityFilter: TResampleFilter;
  iAddBorder: Boolean;
  iBorderColor: TColor;
  iAddShadow: Boolean;
  iBlurRadius: Integer;
  iShadowOffset: Integer;
  iShadowColor: TColor;
  iBackgroundColor: TColor;
  iIEBitmap: TIEBitmap;
begin
  tmrUpdatePreview.Enabled := False;
  if chkPreview.checked = False then
    ImageEnView1.Blank
  else if ImageEnView1.IO.Params.Filename <> IEFolderMView.SelectedFilename then
  begin
    if IEFolderMView.SelectedFilename = '' then
      ImageEnView1.Blank
    else
    begin
      { Set the thumbnail parameters }
      iMaxX := ImageEnView1.ClientWidth;
      iMaxY := ImageEnView1.ClientHeight;
      iCanStretch := False;
      iQualityFilter := rfLanczos3;
      iAddBorder := True;
      iBorderColor := clWhite;
      iAddShadow := True;
      iBlurRadius := 4;
      iShadowOffset := 4;
      iShadowColor := clBlack;
      iBackgroundColor := clWhite;
      { If thumbnail is checked then get the image from IEFolderMView and
        convert it to a thumbnail.  Assign the thumbnail to ImageEnView1 and
        update ImageEnView1. Then release the bitmap to prevent memory leak! }
      if Thumbnail1.Checked then
      begin
        iIEBitmap := IEFolderMView.GetTIEBitmap(IEFolderMView.SelectedImage);
        iIEBitmap.IEConvertToThumbnail(iMaxX, iMaxY, iCanStretch,
          iQualityFilter, iAddBorder, iBorderColor, iAddShadow, iBlurRadius,
          iShadowOffset, iShadowColor, iBackgroundColor);
          ImageEnView1.IEBitmap.Assign(iIEBitmap);
        ImageEnView1.Update;
        IEFolderMView.ReleaseBitmap(IEFolderMView.SelectedImage);
      end
      else
      { Load the image from a file }
      begin
        ImageEnView1.IO.LoadFromFile(IEFolderMView.SelectedFilename);
      end;
    end;
  end;
end;