If I visited Saudi Arabia with my wife, she’d wear a hijab. It would be a show of humility and respect and there’s nothing unchristian about it. However, if she was in some position of authority it would be inappropriate (like when Bush’s chicks donned hijabs in an act of dhimmitude). I think Michelle is a vile, hate filled, goon who can’t conceal her hatred for the world, but her attire in this photo seems fine.
I’m glad she didn’t wear the veil. However for a state event, especially something related to the death of a leader, her dress is significantly too informal.