I certainly think you are getting into a blue ocean, It is a great concept but it does not promote quality but a follower base and quantity, that is the thing I love about https://unsplash.com/. How does the reward system work? It seems that you are giving away big sums of money for little to no effort.
RE: Steepshot for the Web is getting better. Responsive layout, image rotation, enhancements and more updates. Prize for the best user review.