Facebook doesn’t show image preview of shared link

  1. open-graph-logoCheck FB debuger https://developers.facebook.com/tools/debug/og/object?q=hostname.sk
  2. check HTTP response code of your webserver in access log – should be HTTP/1.1 200 OK (Facebook goes to IPv6 address by default)
    tail -f /var/log/nginx/access.log
    2a03:2880:2110:9ff4:: - - [20/Feb/2014:01:06:08 +0100] 
        "GET /index.php HTTP/1.1" 301 0 "-" 
            "facebookexternalhit/1.1 (+http://www.facebook.com/externalhit_uatext.php)"
  3.  check configuration of your nginx and/or apache – virtualhost should listen on IPv6 address too, if you have AAAA record
    server {
          server_name blog.hostname.sk www.blog.hostname.sk;
          listen *:80;
          listen [::]:80;
  4. check Open Graph tags:
    <meta property="og:title" content="Ako som chybu v SK-NIC štatistikách našiel | Blog Ľubomíra Hosta">
    <meta property="og:image" content="http://blog.hostname.sk/wp-content/uploads/2014/02/sknic-domains-count-comparison-300x185.png">
    <meta property="og:type" content="article">
    <meta property="og:url" content="http://blog.hostname.sk/2014/02/17/ako-som-chybu-v-sk-nic-statistikach-nasiel/">
    <meta property="og:description" content="súkromný blog">
    <meta property="og:site_name" content="Blog Ľubomíra Hosta">