Hi Ivo,
just an odd problem: the thumbnail in j2store cart module disappeared after updating the template. Previously, when I downloaded the quickstart package and after the update to Joomla 3.8.1, everything worked perfectly.
I also updated J2store version to 3.2.26 (the latest one) and notified the producer about this problem (still waiting for the reply...Indian support has different hours from European

)
I cleaned the cache of Joomla, browsers (Safari and Chrome) and of Gantry, but no success. Unfortunately I'm working on localhost and can't give you an online URL
Thanks a million for your reply