Facebook link share button with dynamic thumbmail image

VERY URGENT! I need you to make a share button like the one you can see at the result page of this quiz: [login to view URL] I have a code that generates a base64 image based on the answers of the user on certain question. - Convert a user generated image from base64 to png - Automatically upload the converted image to my server - Append the image to the advanced Facebook sharing options: A Facebook app may be needed is needed Result when clicking on "share with facebook" the user will share the link to the web page and as preview image he will share its own generated image. Please, if you are not able to do what I am asking don't let me waste my time. You need to know PHP and Javascript (Jquery probably), it's a server based task good in order to achieve in this challenge. I'm using Wordpress, as fair as this can make a difference. You can see my code as it is until now here: [login to view URL]