my suggestion is that as the photos are loaded by the models, the latest one are at the top of the page , and ones which are several years old are at the bottom . Disregardless of content. Hence a true indication of the looks and hair style of the model is seen straight away .
Uhh, obvious flaw: what if they don't upload their images in date order?
Similarly, I see plenty of members who "recirculate" their images multiple times, in order to have them reappear on the site's frontpage for a bit of free publicity. Wouldn't that mess your plan up too?
Why should your not wishing to take the trouble to look through the portfolio take priority over models' wishes as to how they display their photos?
Come to think of it, shouldn't your portfolio be laid out in strict chronological order so that models can see if your image quality is improving?