I think there's indeed one more strategy to have in relation to pinterest.
1. already established informational sites: they get their images stolen and I've yet to see anybody get anything useful out of pinterest at all. To these web masters pinterest and their users are nothing but scrapers.
2. those selling things might not mind their images being used without permission and might welcome any little bit of traffic they can get, convert or not.
3. you apparently also can go "made for pinterest", and apparently there's possibility for some success in that in certain niches. I guess you need to be more in tune with their (female) audience, and willing to take a risk coupling your fate to theirs.