Google is location-agnostic, though will act like it cares about location depending on the location of the search. If it pulled the wrong thumbnail for you, it got there via a link (internal or external) and felt that is an appropriate result. What you do now depends on your goal (change the thumbnail for example).
It's good that you appear with a geo-targeted piece of content. This means you're responding to local searches. Google will show different SERP results for every person and location, so there isn't much value/concern over how they see your site. They see it from "all" locations.