I am not too familiar with this, I did do what you suggested with the Facebook debugger and got this, as follows:
Like Button Warnings That Should Be Fixed
Like Button Tag Missing: og:image is missing. The og:image meta tag is necessary for Facebook to render a News Feed story that generates a high click-through rate.
Open Graph Warnings That Should Be Fixed
Inferred Property: The 'og:image' property should be explicitly provided, even if a value can be inferred from other tags.
Small og:image: All the images referenced by og:image should be at least 200px in both dimensions. Please check all the images with tag og:image in the given url and ensure that it meets the recommended specification.
Mismatch og:url and canonical url: og:url tag in the header is not the same URL as rel='canonical' link in the html.
Can you please elaborate in laymen terms? Thank you very much. Is this a simple fix?