For legal reasons it's critical to fully explain the license on the photos available for download, and the terms for anybody submitting the photos. Unfortunately it's really not enough to just say: "Free hi-resolution photos for your website."
Sorry to go off-topic, but MVPs are meant to be extreme! That's the whole point. Maybe OP has no idea about licenses or the necessity of them. Had they not posted this, all these lovely comments on the matter would have never been written!
Unfortunately we live in a legal environment where the author stating "free for commercial and personal use" is not a licence strong enough to hold up under law.
(Use the CC stuff if you can.)
I don't know why. But I laughed so hard on this.