You are absolutely right that Kim should have told Karen she didn't want her at the catering thing, but the results would have been the same or worse. It was horrible that Karen's hissy fit kept her from supporting her daughter and meeting the in-laws. It was vindictive and childish and I wouldn't have taken pictures of those dresses to save my life. I'd tell my mother to wear whatever the hell she wanted but not to expect to be in any family pictures unless it's appropriate.