Public Function SetImageAlpha(ByVal Image As Bitmap, ByVal bTopTransparent _
      As Boolean) As Image
 
        Dim NewImage As New Bitmap(Image.Width, Image.Height)
        NewImage.SetResolution(Image.HorizontalResolution, _
          Image.VerticalResolution)
 
        For nCol As Integer = 0 To NewImage.Width - 1
            For nRow As Integer = 0 To NewImage.Height - 1
                Dim nAlpha As Integer
                If bTopTransparent Then
                    nAlpha = 255 * (nRow / (NewImage.Height - 1))
                Else
                    nAlpha = 255 - (255 * (nRow / (NewImage.Height - 1)))
                End If
                NewImage.SetPixel(nCol, nRow, Color.FromArgb(nAlpha, _
                  Image.GetPixel(nCol, nRow)))
            Next
        Next
 
        Return NewImage
 
    End Function