My colleague Stephen Griffin recently blogged about how to show or hide the Sender Contact Photo feature in Outlook.  Since he only supplied the C++ version the product team asked me to supply the .NET version.  [Edit: 2/10/2014:  It has come to my attention that the code below will only work for Outlook 2010.  Support for this was removed in Outlook 2013.]

Visual Basic

Public Sub SetSenderContactPhoto(ByVal Inspector As Object, ByVal ShowSenderContactPhoto As Boolean)
  Dim typeInspector As Type = Inspector.GetType()
  Dim dispidShowSenderPhotoMemberName As String = String.Format("[DispID={0}]", _ 
  Dim args() As Object = {ShowSenderContactPhoto}
    typeInspector.InvokeMember(dispidShowSenderPhotoMemberName, _ 
        System.Reflection.BindingFlags.InvokeMethod, _
        Nothing, _
        Inspector, _
  Catch comEx As System.Runtime.InteropServices.COMException

  End Try
End Sub



void SetSenderContactPhoto(object Inspector, bool ShowSenderContactPhoto)
  Type typeInspector = Inspector.GetType();
  string dispidShowSenderPhotoMemberName = String.Format("[DispID={0}]", 0xF0D0);
  object[] args = {ShowSenderContactPhoto};

  catch(System.Runtime.InteropServices.COMException comEx)