Dim Layer As New Bitmap(64,64)
Dim f As Graphics = Graphics.FromImage(Layer)
f.DrawImage(Tileset, New Rectangle(0, 0, 64, 64),NTR(Number) , _
  GraphicsUnit.Pixel)
 
    Private Function NTR(ByVal Number As Integer) As Rectangle
        Number -= 1
        Return New Rectangle((Number Mod 8) * 64, ((Number - (Number Mod 8)) / _
          8) * 64, 64, 64)
    End Function