var
  i, iidx: integer;
begin
  // prompt user to select a device
  ImageEnMView1.MIO.SelectAcquireSource([ieaWIA]);

  // loop among children of Device (the root item)
  for i:=0 to ImageEnMView1.MIO.WIAParams.Device.Children.Count-1 do
    // process only images
    if witImage in TIEWiaItem(ImageEnMView1.MIO.WIAParams.Device.Children[i]).ItemType then
      with ImageEnMView1.MIO.WIAParams, Device do
      begin
        // add new empty image
        iidx := ImageEnMView1.AppendImage(1, 1);  
        // get thumbnail and store in TImageEnMView bitmap
        GetItemThumbnail(Children[i], ImageEnMView1.GetTIEBitmap(iidx));  
        // close GetTIEBitmap()
        ImageEnMView1.ReleaseBitmap(iidx);  
        // just to associate TImageEnMView item with WIA item
        ImageEnMView1.ImageUserPointer[iidx] := Children[i];  
      end;
end;

procedure TForm1.ImageEnMView1ImageSelect(Sender: TObject; idx: Integer);
begin
  ImageEnView1.IO.WIAParams.ProcessingBitmap := ImageEnView1.IEBitmap;
  ImageEnView1.IO.WIAParams.Transfer( ImageEnMView1.ImageUserPointer[idx] , false);
  ImageEnView1.Update;
end;