Dim bmp As Bitmap = New Bitmap(PicBox.Width, PicBox.Height)
Try
   Dim g As Graphics = Graphics.FromImage(bmp)
   Try
      g.Clear(PicBox.BackColor)
      g.DrawImage(PicBox.Image, 0, 0)
      bmp.Save("TestBild1.bmp")
   Finally
      g.Dispose()
   End Try
Finally
   bmp.Dispose()
End Try