Why is the Wix information and thumbnail, shared on Facebook, not up to date?
Please make sure that you have added your personal Facebook Account username (and not your Business page username) under the Social Settings section of your Wix account.
To add a Facebook username: From the left side of your Editor, click Settings > click Social Settings > under Facebook Username, type your username > click Done.
The Facebook API only works with personal Facebook account usernames. Any features related to your Facebook Page (sharing your website on Facebook, managing comments, likes and etc), require administrator identification on Facebook. The owner of the page will be set as the administrator of all the pages he has, which is why the personal Facebook username is required. This information is not displayed to users who visit your site, it is only for the purpose of Facebook admin related functions.
Note: The user name is not your name on Facebook, it appears in the location bar of your browser after "https://www.facebook.com/" when you view your personal Timeline page.