When using the powerful and free Puock theme in WordPress, you might encounter a problem where the thumbnails do not display.

Thumbnails not displaying.

This issue primarily occurs when the official URL rewriting rules are enabled in the backend, along with the use of uppercase file extensions for images, such as xxxx.PNG or xxxxx.JPG.

Solution:

The solution is to change the image file extensions to lowercase, specifically to png.

Now displaying correctly.