Оформил: DeeCo
Автор: http://www.swissdelphicenter.ch

procedure TForm1.Button1Click(Sender: TObject);
 var
   ico: TIcon;
 begin
   ico := TIcon.Create;
   try
     Imagelist1.GetIcon(0, ico); // Get first icon from Imagelist1 
    Imagelist2.AddIcon(ico); // Add the icon to Imagelist2 
  finally
     ico.Free;
   end;
 end;