[RESOLVED] LockBits has different effect?

[minitech]

Hi, I've made an Aero-style form header (see signature) and I wanted to speed it up, so I used LockBits, and it had a different effect. These two methods should do the same thing, right? Well, it doesn't. Image 1 is before LockBits, Image 2 is after. Using LockBits gives a streaking effect that I don't like. What's happening?

Private Sub BlurImage(ByVal img As Bitmap, Optional ByVal radius As Integer = 3, Optional ByVal blur_bounds As Object = Nothing)
        Dim bb As Rectangle
        If blur_bounds IsNot Nothing Then
            bb = CType(blur_bounds, Rectangle)
        Else
            bb = New Rectangle(0, 0, img.Width, img.Height)
        End If
        Dim i As Integer
        For i = 0 To radius
            Dim y, x As Integer
            For y = bb.Y To bb.Bottom - 1
                For x = bb.X To bb.Right - 1
                    Try
                        Dim px_up As Color = img.GetPixel(x, y - 1)
                        Dim px_down As Color = img.GetPixel(x, y + 1)
                        Dim px_left As Color = img.GetPixel(x - 1, y)
                        Dim px_right As Color = img.GetPixel(x + 1, y)
                        Dim pxR As Integer = Average_Int(px_up.R, px_down.R, px_left.R, px_right.R)
                        Dim pxG As Integer = Average_Int(px_up.G, px_down.G, px_left.G, px_right.G)
                        Dim pxB As Integer = Average_Int(px_up.B, px_down.B, px_left.B, px_right.B)
                        Dim n_px As Color = Color.FromArgb(255, pxR, pxG, pxB)
                        img.SetPixel(x, y, n_px)
                    Catch ex As Exception
                    End Try
                Next
            Next
        Next
    End Sub
    Private Sub BlurImageLockBits(ByVal img As Bitmap, Optional ByVal radius As Integer = 3, Optional ByVal blur_bounds As Object = Nothing)
        Dim bb As Rectangle
        If blur_bounds IsNot Nothing Then
            bb = CType(blur_bounds, Rectangle)
        Else
            bb = New Rectangle(0, 0, img.Width, img.Height)
        End If
        Dim bdata As Imaging.BitmapData = img.LockBits(bb, Imaging.ImageLockMode.ReadWrite, Imaging.PixelFormat.Format32bppArgb)
        Dim img_info(bdata.Width * bdata.Height) As Integer
        System.Runtime.InteropServices.Marshal.Copy(bdata.Scan0, img_info, 0, img_info.Length)
        Dim i As Integer
        For i = 0 To radius
            Dim y, x As Integer
            For y = bb.Y To bb.Bottom - 1
                For x = bb.X To bb.Right - 1
                    Try
                        Dim px_up As Color = Color.FromArgb(img_info(((y - 1) * bdata.Width) + x))
                        Dim px_down As Color = Color.FromArgb(img_info(((y + 1) * bdata.Width) + x))
                        Dim px_left As Color = Color.FromArgb(img_info((y * bdata.Width) + x - 1))
                        Dim px_right As Color = Color.FromArgb(img_info((y * bdata.Width) + x + 1))
                        Dim pxR As Integer = Average_Int(px_up.R, px_down.R, px_left.R, px_right.R)
                        Dim pxG As Integer = Average_Int(px_up.G, px_down.G, px_left.G, px_right.G)
                        Dim pxB As Integer = Average_Int(px_up.B, px_down.B, px_left.B, px_right.B)
                        Dim n_px As Color = Color.FromArgb(255, pxR, pxG, pxB)
                        img_info((y * bdata.Width) + x) = n_px.ToArgb()
                    Catch ex As Exception
                    End Try
                Next
            Next
        Next
        System.Runtime.InteropServices.Marshal.Copy(img_info, 0, bdata.Scan0, img_info.Length)
        img.UnlockBits(bdata)
    End Sub