Dim imageFile As Image = Image.FromFile("MyImage.jpg")

' Create graphics object for alteration.
Dim newGraphics As Graphics = Graphics.FromImage(imageFile)

' Alter image.
newGraphics.FillRectangle(New SolidBrush(Color.Black), _
100, 50, 100, 100)

' Draw image to screen.
newGraphics.Graphics.DrawImage(imageFile, New PointF(0.0F, 0.0F))

Imports System.Runtime.InteropServices
            Class Form1

                Private InitialStyle As Integer
                Dim PercentVisible As Decimal
                Private Sub Form1_Load(sender As Object, e As RoutedEventArgs) Handles Form1.Load
                    InitialStyle = GetWindowLong(Me.Handle, -20)
                    PercentVisible = 0.8

                    SetWindowLong(Me.Handle, -20, InitialStyle Or &H80000 Or &H20)

                    SetLayeredWindowAttributes(Me.Handle, 0, 255 * PercentVisible, &H2)

                    Me.Topmost = True
                End Sub

                <DllImport("user32.dll", EntryPoint:="GetWindowLong")> Public Shared Function GetWindowLong(ByVal hWnd As IntPtr, ByVal nIndex As Integer) As Integer
                End Function

                <DllImport("user32.dll", EntryPoint:="SetWindowLong")> Public Shared Function SetWindowLong(ByVal hWnd As IntPtr, ByVal nIndex As Integer, ByVal dwNewLong As Integer) As Integer
                End Function

                <DllImport("user32.dll", EntryPoint:="SetLayeredWindowAttributes")> Public Shared Function SetLayeredWindowAttributes(ByVal hWnd As IntPtr, ByVal crKey As Integer, ByVal alpha As Byte, ByVal dwFlags As Integer) As Boolean
                End Function
            End Class