画像ファイルをico拡張子で保存したい場合

画像ファイルをico拡張子で保存したい場合
VB.NET

<System.Runtime.InteropServices.DllImport( _
    "user32.dll", _
    CharSet:=System.Runtime.InteropServices.CharSet.Auto)> _
Private Shared Function DestroyIcon(ByVal handle As IntPtr) As Boolean
End Function

Private Sub btn1_Click(ByVal sender As Object, _
        ByVal e As EventArgs) Handles btn1.Click

    Dim iconFile As String = "C:\test\1.ico"

    Dim bmp As New Bitmap(32, 32)

    Dim g As Graphics = Graphics.FromImage(bmp)
    g.FillEllipse(Brushes.Red, 1, 1, 30, 30)
    g.Dispose()

    Dim ico As Icon = System.Drawing.Icon.FromHandle(bmp.GetHicon())

    Dim fs As New System.IO.FileStream(iconFile, _
        System.IO.FileMode.Create, System.IO.FileAccess.Write)
    ico.Save(fs)
    fs.Close()

    ico.Dispose()
    bmp.Dispose()

    DestroyIcon(ico.Handle)
End Sub

C#

[System.Runtime.InteropServices.DllImport(
    "user32.dll",
    CharSet = System.Runtime.InteropServices.CharSet.Auto)]
extern static bool DestroyIcon(IntPtr handle);

private void btn1_Click(object sender, EventArgs e)
{
    string iconFile = "C:\\test\\1.ico";

    Bitmap bmp = new Bitmap(32, 32);

    Graphics g = Graphics.FromImage(bmp);
    g.FillEllipse(Brushes.Red, 1, 1, 30, 30);
    g.Dispose();

    Icon ico = System.Drawing.Icon.FromHandle(bmp.GetHicon());

    System.IO.FileStream fs = new System.IO.FileStream(
        iconFile, System.IO.FileMode.Create, System.IO.FileAccess.Write);
    ico.Save(fs);
    fs.Close();

    ico.Dispose();
    bmp.Dispose();

    DestroyIcon(ico.Handle);
}