Although it is indeed something interesting, there will always be people who are paying a dollar per picture, or 5 dollars per video and others who are not even paying a cent... but each compensates the other and every picture made is there forever to convert new users and retain the existing ones, and will be paid for many times.
Personally, I am developing my own CMS for our future paysites, and it indeed has a tracking method for pictures viewed and videos downloaded, so I will know about this
