Facebook caches the poster frame, title, and description when you first paste the url anywhere in their system. If you have updated any of this data, you will need to tell Facebook to “Scrape” this information again. Do so by:
Go to the following Facebook URL (https://developers.facebook.com/tools/debug/)
Enter the mediazilla url into the field and click ‘Debug’
On the following page, click ‘Scrape Again’