"Out there" in this case means "out in the wider world" as Su.Ki. mentioned. In this case, it means out on the Internet. If something gets you out there though, it makes you noticed by fans and other people. That is, by posting these photos on Facebook and other social media sites, it connects you with an audience... perhaps current customers who already frequent the restaurant or even new people who never even knew about the restaurant until they saw the photos. This is a great way to gain new business. :)