Dim bmpNew As Bitmap = getBitmap()
        Dim bd As New Imaging.BitmapData
        bd = bmpNew.LockBits(New Rectangle(0, 0, bmpNew.Width, bmpNew.Height), _
          Imaging.ImageLockMode.ReadWrite, bmpNew.PixelFormat)
        Dim byt(bd.Stride * bd.Height) As Byte
        Runtime.InteropServices.Marshal.Copy(bd.Scan0, byt, 0, byt.Length) 
        For i As Integer = 0 To byt.Length - 1
            byt(i) = CByte(255) - byt(i)
        Next i
        Runtime.InteropServices.Marshal.Copy(byt, 0, bd.Scan0, byt.Length)
        bmpNew.UnlockBits(bd)
        hf.addViewer(bmpNew)