Dim _Bitmap As New Bitmap("winnt256.bmp")
  Dim _Bitmap_tmp As New Bitmap(_Bitmap)
  Dim bColor As Color = _Bitmap.GetPixel(1, 1)
  _Bitmap.MakeTransparent(bColor)
  _Bitmap = _Bitmap_tmp ' ZURÜCKSCHREIBEN / WIEDERHERSTELLEN
  e.Graphics.DrawImage(_Bitmap, _Bitmap.Width, 0, _Bitmap.Width, _Bitmap.Height)