Hello,
Here is what we can see now – https://gyazo.com/5e38724ea51de4214a63e07575086880
To find out why thumbnail images are not loaded, try to disable all the third-party plugins (including cache plugins), that do not come bundled with XStore https://xstore.helpscoutdocs.com/article/36-included-plugins , clear the cache of the browser, and check then. Maybe one of the additional plugins is the reason for the problem.
Regards