Hello,
First of all, thank you for your purchase.
I checked your site and it seems you don’t have an “og:image” meta tag added to the HTML content of your site. This tag is used by social networks to grab the image of articles, if it is missing, the images might not be displayed correctly on their side.
To fix this, I suggest you install a SEO plugin, like Yoast https://wordpress.org/plugins/wordpress-seo/ or All In One SEO https://wordpress.org/plugins/all-in-one-seo-pack/ and set it up, so the “og:image” meta tags are added correctly to the post content.
If you already have a SEO plugin installed on your site, I suggest you check its settings, as it might have the “og:image” tag creation turned off.
Regards, Szabi – CodeRevolution.