Add-Type -AssemblyName System.Drawing
$img = [System.Drawing.Image]::FromFile("Down_nb-02.png")
$fs = [System.IO.File]::Create("Down_nb-02.ico")
$bitmap = new-object System.Drawing.Bitmap($img, 256, 256)
$icon = [System.Drawing.Icon]::FromHandle($bitmap.GetHicon())
$icon.Save($fs)
$fs.Close()
$img.Dispose()
$bitmap.Dispose()