First off, have you measured the time it takes to load your site? It seems awfully slow to me (maybe it's the HN posting that's slowing it down) and could be a reason people are not spending more time on the site.

Before you change your vision, have you considered reducing the friction to use the site? Having to email photos and put in the name of the restaurant is cumbersome compared to opening a phone app and taking a picture that automatically gets posted to the site with your location from the phone's gps.

What sets this site apart from the other food photo based sites?