[FOSDEM] Improve main picture on website for use in social media

Hi all, Could the website offer a nice main image for usage in social media? If you share a link to http://fosdem.org/2016 on Twitter, LinkedIn, Facebook, Google+ and so on, the map of the campus is being shown as image, which is not the most representable image for the event. It is possible to indicate in the website (hidden or not) which picture/logo should be picked up by social media when sharing the link of the site. Could someone have a go at improving this? Thanks, Pander