Public Class Form1
    Private tileset As Bitmap = Bitmap.FromFile("d:\08.11.01-01.BMP") ' großes 
    ' bild 1024*1600 punkte
 
    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
 
    Private Sub NumericUpDown1_ValueChanged(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles NumericUpDown1.ValueChanged
        Dim Layer As New Bitmap(64, 64)
        Dim f As Graphics = Graphics.FromImage(Layer)
        f.DrawImage(tileset, New Rectangle(0, 0, 64, 64), NTR( _
          NumericUpDown1.Value), GraphicsUnit.Pixel)
        PictureBox1.Image = Layer
        Layer = Nothing
    End Sub
End Class

Gru?

Silver