Social Sharing issues

Hello! I am having problems with the Social Sharing option.

I have several grades depending on the result. Each grade description is an image, and aparently this is giving problems with the social sharing.

{{{grade-description}}} is not working with Social Sharing when it is an image, it only works if it’s plain text. Any way of solving this? Also, I keep on assignin an URL for the custom Facebook Button, but it makes no difference, it always shows the standard “like” button.

The page I need help with: [log in to see the link]