Public Shared Sub InvertColors(ByRef bmp As Bitmap)
Dim cSource As Color
Dim cDest As Color
For y As Integer = 0 To bmp.Height - 1
For x As Integer = 0 To bmp.Width - 1
cSource = bmp.GetPixel(x, y)
cDest = Color.FromArgb(255 - cSource.R, 255 - cSource.G, 255 - cSource.B)
bmp.SetPixel(x, y, cDest)
Next
Next
End Sub