Image When Posting Link

Hi,

I have GeneratePress installed with a Child theme called Active. What I cannot figure out is what setting do I change to select an image so that when I copy and paste my stores link, to say Facebook, it’s shows and image instead of a white box.

I know I am probably not describing it too well but usually when I post links they show the main pages image or something else the Web Master has set. But when I past my link, it is just a white background.

I also purchased all the addons for GeneratePress so maybe it is in one of those?