There are a group of law firms going after these prosecutions and they seem to have some success. They offer a variety of free and paid services.
I don't know them and have never dealt with them, but their arguments seem to make sense.
One of the most interesting is that cops (ON DUTY) have been recieving these photo tickets (and we all know cops never break the law). As a result, in San Diego (where these lawyers are), and other places, some of these tickets are getting dismissed.