Public Function GetColors(ByVal bmp As Bitmap) As PfadList
        Dim rect As New Rectangle(0, 0, bmp.Width, bmp.Height)
        Dim bd As Imaging.BitmapData = bmp.LockBits(rect, _
          Imaging.ImageLockMode.ReadOnly, _
          Imaging.PixelFormat.Format32bppArgb)
        Dim byt As Int32 = (bd.Stride * bmp.Height) - 1
        Dim col(byt) As Byte
        Runtime.InteropServices.Marshal.Copy(bd.Scan0, col, 0, byt)
        bmp.UnlockBits(bd)
        Dim lst As New PfadList
        For y As Int32 = 0 To bmp.Height - 1
            For x As Int32 = 0 To bd.Stride - 4 Step 4
                Dim item As New Pfad
                item.X = x / 4
                item.Y = y
                item.Farbe = Color.FromArgb(col(x + y * bd.Stride + 3), col(x + _
                  y * bd.Stride + 2), col(x + y * bd.Stride + 1), col(x + y * _
                  bd.Stride))
                lst.Add(item)
            Next
        Next
        Return lst
    End Function
    Function ToRegion(ByVal Bitmap As Bitmap, ByVal TransparentColor As Color) _
      As Region
        Dim pth As PfadList = GetColors(Bitmap)
        Dim pf As New Drawing2D.GraphicsPath
        For i As Integer = 0 To pth.List.Count - 1
            If pth.List(i).Farbe.A <> TransparentColor.A Or pth.List( _
              i).Farbe.R <> TransparentColor.R Or pth.List(i).Farbe.G <> _
              TransparentColor.G Or pth.List(i).Farbe.B <> TransparentColor.B Then
                pf.AddRectangle(New RectangleF(pth.List(i).X, pth.List(i).Y, 1, _
                1))
            End If
        Next
        Return New Region(pf)
    End Function
Public Class Pfad
    Private m_Farbe As Color
    Private m_X As Integer
    Private m_Y As Integer
    Property X() As Integer
        Get
            Return m_X
        End Get
        Set(ByVal value As Integer)
            m_X = value
        End Set
    End Property
    Property Y() As Integer
        Get
            Return m_Y
        End Get
        Set(ByVal value As Integer)
            m_Y = value
        End Set
    End Property
    Property Farbe() As Color
        Get
            Return m_Farbe
        End Get
        Set(ByVal value As Color)
            m_Farbe = value
        End Set
    End Property
 
End Class
Public Class PfadList
    Private m_List As New List(Of Pfad)
    Property List() As List(Of Pfad)
        Get
            Return m_List
        End Get
        Set(ByVal value As List(Of Pfad))
            m_List = value
        End Set
    End Property
    Sub Add(ByVal Item As Pfad)
        m_List.Add(Item)
    End Sub
    Function GetColor(ByVal X As Integer, ByVal Y As Integer) As Color
        For i As Integer = X * Y To m_List.Count - 1
            If m_List(i).X = X And m_List(i).Y = Y Then
                Return m_List(i).Farbe
                Exit For
            End If
        Next
    End Function
End Class

PictureBox1.Region = ToRegion(New Bitmap("C:\Deinbild.bmp"),Color.Magenta)
PictureBox1.Image = New Bitmap("C:\Deinbild.bmp")