ExecuteNonQuery Connection non initialisé

Merci de m'indiquer ce qui ne vas pas dans ce bout de code qui génére une erreur

Private Sub BtnMaj_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnMaj.Click
Dim CN1 As SqlConnection = New SqlConnection("Data Source=server;Initial Catalog=DTATA.MDF;Integrated Security=True")
Dim Cmd As New SqlCommand("Update Apparts Set (Photo03 = Imag3, Photo04 = Imag4,Photo02 = Imag2,PhotoO1 = Imag1")
' Cmd.CommandType = CommandType.Text
Cmd.Parameters.Add(New SqlParameter("@Photo03", DirectCast(Imag3, Object)))
Cmd.Parameters.Add(New SqlParameter("@PhotoO4", DirectCast(Imag4, Object)))
Cmd.Parameters.Add(New SqlParameter("@Photo02", DirectCast(Imag2, Object)))
Cmd.Parameters.Add(New SqlParameter("@PhotoO1", DirectCast(Imag1, Object)))
Try
CN1.Open()
Cmd.ExecuteNonQuery()
CN1.Close()
Catch ex As Exception
MsgBox(ex.Message)
End Try

End Sub