When you share a page URL on a social network, it extracts the information from your site to define which image and text will be included in the share. This is not controlled by GetSocial.
You can get an idea of how Facebook 'sees' your page with the following steps:
- Access https://developers.facebook.com/tools/debug/og/object/
- Insert the page's URL in the Input URL field
- Click in "Fetch new scrape information"
If you're using WordPress and you want to control what is displayed on your shares, I recommend you to use a plugin such as https://wordpress.org/plugins/wordpress-seo/, https://wordpress.org/plugins/add-meta-tags/ or https://wordpress.org/plugins/all-in-one-seo-pack/ where you can define the open graph meta tags used by Facebook to choose the image and text included in the share.
There's also a great article about this here: https://stackoverflow.com/questions/1138460/how-does-facebook-sharer-select-images-and-other-metadata-when-sharing-my-url