Mug shots and photo analysis

I've been rereading Colleen Fitzpatrick's book The Dead Horse Investigation: forensic photo analysis for everyone. Coincidentally an item in the new issue of the Lost Cousins newsletter, at http://lostcousins.com/newsletters/apr10news.htm refers to top websites for dating UK photographs, taken from an article in Who Do You Think You Are? magazine. They are:

(1) Victorian & Edwardian photographs has an enormous collection of photographs that you can compare against your own

(2) PhotoLondon has a database of 9000 photographers who worked in the London area, with short biographical notes that will help you date the photographs they took.

(3) Early Photographers has a dating calculator for postcards and cartes de visite

(4) Great War Forum would be useful if you have a photograph of your ancestor in uniform

(5) Wedding Fashion has photographs of wedding dresses from the Victorian era onwards