I think advertising for top international clients. Even if the day rate is not spectacular you can get lucky with buy outs for new countries and more years for work you dod a while ago and already forgot about. If you have a few jobs like that every year i suppose it can stack up quite fast. I have only had two of those jobs but it made me go, “ah so this is how you make crazy photo money”.

But i think the way to go is to go somewhere really niche, outsode of the general competition. Like the guy who shoots Apple products. Or All Of The Beers.