uses Office2000,Excel2000,....    ....
  ((ExcelApplication1.ActiveWorkbook AS _WorkBook).ActiveSheet AS _WorkSheet).Shapes.Item('Picture 1').ScaleWidth(2,msoFalse,msoScaleFromTopLeft);
  ((ExcelApplication1.ActiveWorkbook AS _WorkBook).ActiveSheet AS _WorkSheet).Shapes.Item('Picture 1').ScaleHeight(2,msoFalse,msoScaleFromTopLeft);
....    或是
....
  with ((ExcelApplication1.ActiveWorkbook AS _WorkBook).ActiveSheet AS _WorkSheet).Shapes.Item('Picture 1') do
  begin
    Width := Width * 0.5;
    Height := Height * 0.5;
  end;
....