請教高手如何把 .bmp file change to .ico file .bmp改成.ico感恩 謝謝

http://groups.google.com.tw/groups?hl=zh-TW&lr=&ie=UTF-8&th=3f8f849638920ac0&rnum=1

function BitmapToIcon(Bitmap: TBitmap): TIcon;
var
  IconSizeX, IconSizeY : integer;
  IconInfo: TIconInfo;
  IconBitmap, MaskBitmap: TBitmap;
  x, y: Integer;
  TransparentColor: TColor;
begin
  IconSizeX := GetSystemMetrics(SM_CXICON);
  IconSizeY := GetSystemMetrics(SM_CYICON);
  IconBitmap:= TBitmap.Create;
  IconBitmap.Width:= IconSizeX;
  IconBitmap.Height:= IconSizeY;
  IconBitmap.Canvas.StretchDraw(Rect(0, 0, IconSizeX, IconSizeY), Bitmap);
  IconBitmap.TransparentColor:= Bitmap.TransparentColor;
  TransparentColor:= IconBitmap.TransparentColor and $FFFFFF;
  MaskBitmap:= TBitmap.Create;
  MaskBitmap.Assign(IconBitmap);
  for y:= 0 to IconSizeY - 1 do
    for x:= 0 to IconSizeX - 1 do
      if IconBitmap.Canvas.Pixels[x, y] = TransparentColor then
        IconBitmap.Canvas.Pixels[x, y]:= clBlack;
  IconInfo.fIcon:= True;
  IconInfo.hbmMask:= MaskBitmap.MaskHandle;
  IconInfo.hbmColor:= IconBitmap.Handle;
  Result:= TIcon.Create;
  Result.Handle:= CreateIconIndirect(IconInfo);
  MaskBitmap.Free;
  IconBitmap.Free;
end;

icon:=bitmaptoicon(bm); Image2.Canvas.Draw(0,0,icon); Image2.Picture.SaveToFile('test'); 如上 試過後在image2可成功畫出 但存檔後 再用delphi image editor 叫出 卻失敗 invalid file format ? why? 請高手告知 感恩

用法如下:

procedure TForm1.Button1Click(Sender: TObject);
var
  ico: TIcon;
begin
  ico := BitmapToIcon(Image1.Picture.Bitmap);
  ico.SaveToFile('c:\xx.ico');
end;

謝謝 hager 成功了 感恩