I have several opinions about that. Part of it is rooted in her narcissism, "look at ME, I'M such a good mom figure". I also wouldn't be surprised if those pictures were posted on her facebook page as public, with the intent that LH and others would see them. She seems to need a lot of attention & approval from external sources, I imagine narcissism is a hungry beast that needs to be constantly fed. Last, it's likely as you suspect, something was rotten in Denmark and she had something to prove to her husband in regards to her ability to care for his children while he was away from home.