(.NET/GDI/BitBlt) Bitmap does not appear correctly using BitBlt   

I have the following code which works fine and puts a transparent image onto 
an image in a Picturebox. The Mask and Src Images are both In PictureBoxes

    Private bmpConv As Bitmap = Nothing
    Private bmpBtl As Bitmap = Nothing
    Private bmpBtlMask As Bitmap = Nothing

           bmpConv = Image.FromFile("..\Images\Conveyor.bmp")
            pbConv.BackgroundImage = bmpConv

            bmpBtl = Image.FromFile("..\Images\Mist50White.bmp")
            pbBtl.BackgroundImage = bmpBtl

            bmpBtlMask = Image.FromFile("..\Images\Mist50Mask.bmp")
            pbBtlMask.BackgroundImage = bmpBtlMask


MyBitBlt(pbConv, pbBtl, pbBtlMask, 0, 0)

    Public Sub MyBitBlt(ByVal Dst As PictureBox, ByVal Src As PictureBox, 
ByVal Mask As PictureBox, ByVal X As Long, ByRef Y As Long)
        ' Get device context of source and destination picture boxes
        Dim srcHDC As IntPtr = Src.CreateGraphics.GetHdc
        Dim dstHDC As IntPtr = Dst.CreateGraphics.GetHdc
        Dim maskHDC As IntPtr = Mask.CreateGraphics.GetHdc

        BitBlt(dstHDC.ToInt32, X, Y, 50, 50, maskHDC.ToInt32, 0, 0, 
TernaryRasterOperations.SRCPAINT)
        'put the picture onto the main screen
        BitBlt(dstHDC.ToInt32, X, Y, 50, 50, srcHDC.ToInt32, 0, 0, 
TernaryRasterOperations.SRCAND)

    End Sub

-- 
IT/Software Dev Manager

date: Thu, 15 May 2008 14:58:01 -0700   author:   Tony (Goody Goody Liquor,Dallas)