I really can’t tell who has the worst looking outfit in that shot. All three are pretty tragic.
I have to say that Flotus should not wear dresses that have a waistline. I don't know what is going on with her body; but, those type of dresses really look awful on her because the waist always seems too high (made worse by her always wearing those belts that look like they are under her armpits or something).
However, the pic that you commented on, with the two chefs, is just incredible. I vote for that photo. There are a lot of pics of her that are not complementary; but, this one is also funny. (And, as an aside, does the color of her sweater actually go with the dress?)