private void traspuestaToolStripMenuItem_Click(object sender, EventArgs e) { try { ImageForm Image1 = (ImageForm)ActiveMdiChild; ImageForm ImageTransposition = new ImageForm(); ImageTransposition.MdiParent = this; ImageTransposition.transposition(Image1.getPicture()); ImageTransposition.Show(); } catch (NullReferenceException) { MessageBox.Show("No hay ninguna foto seleccionada"); } }