Tell me what’s close:

cities = json.load(open(os.path.join("scrape", "cities.json")))

for home in cities:
    home['nearby'] = [city['name_en'] for city in cities if 0 < geo_distance(home['lat'], home['lon'], city['lat'], city['lon']) < 100]

f = codecs.open("scrape/cities.json", "w", "utf-8")
f.write(json.dumps(cities, indent=2, ensure_ascii=False))
f.close()
And send a push message to those in the vicinity of a picture

This sort of wraps up the server-side functionality for now