I know what you mean, it sounds like you want to search or explore by categories. So, when you want to see landmarks, you only see those, but if you wanted to see food, you could filter by that as well. Thanks for the feedback.
Also, these results will be different at different times of day.
Not sure exactly how your app works but maybe you can use the API to check for tags on each photo you load. If any tag contains some word that would relate to food, then just don't load/display it.
I think it's more about finding out what type of location it is: restaurant, bar, club, park, concert venue, whatever. Then filter by that. Rather than the individual photos.
But I like the idea of a "no food pics" option :) Instagram is infamous for stuff like that.
Also, these results will be different at different times of day.