How to update facebook open graph image

this is the most consistent answer I’ve found to this problem: https://stackoverflow.com/a/21468084/339698

If you’re too lazy to go to that link, you can POST an ajax request with the url you are trying to clear:

$.post(
    'https://graph.facebook.com',
    {
        id: 'http://www.site.com/my/share/url/',
        scrape: true
    },
    function(response){
        console.log(response);
    }
);