Private Sub btnBlend_Click(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles btnBlend.Click
    ' Examine the pixels in the label. Make red pixels
    ' grow more transparent to the right and green
    ' pixels grow less transparent to the right.
    Dim bm_label As New Bitmap(picLabel.Image)
    Dim alpha As Integer
    Dim clr As Color
    Dim x As Integer
    Dim y As Integer
    For y = 0 To bm_label.Height - 1
        For x = 0 To bm_label.Width - 1
            clr = bm_label.GetPixel(x, y)
            If clr.G = 0 Then
                ' A red pixel.
                alpha = 255 - CInt(255 * x / bm_label.Width)
            Else
                ' A green pixel. Set alpha = 127.
                alpha = CInt(255 * x / bm_label.Width)
            End If

            bm_label.SetPixel(x, y, _
                Color.FromArgb(alpha, clr.R, clr.G, clr.B))
        Next x
    Next y

    ' Display the result.
    picLabel.Image = bm_label

    ' Copy the label onto the main picture.
    Dim bm_dog As New Bitmap(picDog.Image)
    Dim gr As Graphics = Graphics.FromImage(bm_dog)
    gr.DrawImage(bm_label, _
        (bm_dog.Width - bm_label.Width) \ 2, _
        bm_dog.Height - bm_label.Height)

    ' Display the result.
    picDog.Image = bm_dog
End Sub