The film they ended up making is not so predictable as to make weight the main issue, although there are revealing cameos from the likes of Missy Rayder, who recalls having problems due to the size of her hips (you can see how massive they are in the 'Who is your favourite Rayder' post below).
Instead, Ziff raises a far more original point: the age, and subsequent exploitation, of models, and the lack of regulation preventing this. One model she interviews recalls seeing a 12-year-old with a colouring book backstage at a Chanel show. By all accounts in Picture Me, sexual abuse of models is rife. After all, in what other industry in the world is it "normal" to have 14-year-old girls take their clothes off and be told to act sexy in front of middle-aged men with cameras?
Solve this problem and you're halfway to solving the size issue anyway; puberty will take care of that in large part. Those who say they want to see "real women" on the runway, meaning they want to see someone bigger than a size two, are missing an important point. It should be about their age as much as their size. Thin women are still women; 14-year-old girls are not.