How can I add a thumbnail to my AdFly links on Facebook?

Adding a thumbnail to your AdFly links couldn't be simpler. You just need to click on the pencil icon next to the AdFly link you wish to edit and add a URL to an image for use with Facebook.
In order to test your FB thumbnail please visit following page:
https://developers.facebook.com/tools/debug/og/object/
Paste your AdFly URL and press 'Fetch new scrape information' button.