具体算法请参看《vb.net 教程 5-13 图像处理之像素处理 2》

逆反：

    '逆反
    'http://blog.csdn.net/uruseibest
    Private Sub btnInversion_Click(sender As Object,e As EventArgs) Handles btnInversion.Click
        Dim destImg As New Bitmap(sourceImg.Width,sourceImg.Height)
        Dim sourceData As BitmapData = sourceImg.LockBits(New Rectangle(0,sourceImg.Width,sourceImg.Height),ImageLockMode.ReadOnly,PixelFormat.Format24bppRgb)
        Dim destData As BitmapData = destImg.LockBits(New Rectangle(0,ImageLockMode.WriteOnly,PixelFormat.Format24bppRgb)

        Dim pSource As IntPtr = sourceData.Scan0
        Dim allBytes As Integer = sourceData.Stride * sourceData.Height
        Dim rgbvalues() As Byte
        ReDim rgbvalues(allBytes - 1)
        Marshal.Copy(pSource,rgbvalues,allBytes)

        Dim pos As Integer = 0
        Dim R,G,B As Integer

        For j As Integer = 0 To sourceData.Height - 1
            For i As Integer = 0 To sourceData.Width - 1
                B = 255 - rgbvalues(pos)
                G = 255 - rgbvalues(pos + 1)
                R = 255 - rgbvalues(pos + 2)
                rgbvalues(pos) = B
                rgbvalues(pos + 1) = G
                rgbvalues(pos + 2) = R

                pos = pos + 3
            Next
            pos = pos + sourceData.Stride - sourceData.Width * 3
        Next

        Dim pDest As IntPtr = destData.Scan0
        Marshal.Copy(rgbvalues,pDest,allBytes)

        sourceImg.UnlockBits(sourceData)
        destImg.UnlockBits(destData)

        picDest.Image = destImg
    End Sub

    '曝光
    'http://blog.csdn.net/uruseibest
    Private Sub btnExposure_Click(sender As Object,e As EventArgs) Handles btnExposure.Click
        Dim destImg As New Bitmap(sourceImg.Width,B As Integer

        For j As Integer = 0 To sourceData.Height - 1
            For i As Integer = 0 To sourceData.Width - 1
                B = rgbvalues(pos)
                G = rgbvalues(pos + 1)
                R = rgbvalues(pos + 2)
                If R < 128 Then R = 255 - R
                If G < 128 Then G = 255 - G
                If B < 128 Then B = 255 - B

                rgbvalues(pos) = B
                rgbvalues(pos + 1) = G
                rgbvalues(pos + 2) = R
                pos = pos + 3
            Next
            pos = pos + sourceData.Stride - sourceData.Width * 3
        Next

        Dim pDest As IntPtr = destData.Scan0
        Marshal.Copy(rgbvalues,allBytes)

        sourceImg.UnlockBits(sourceData)
        destImg.UnlockBits(destData)

        picDest.Image = destImg
    End Sub

学习更多vb.net知识，请参看 vb.net 教程 目录