Hi, thanks for you reply!
I’ve tried adding new galleries a lot so I don’t think it’s going to fix things, but I see in the requirements you state that the following is needed:
– The mod_rewrite Apache module
My wordpress installation is running in an Nginx web server, is it possible it may be causing the issue?
And to answer your question, yes all galleries have the same problem, however I am able to see thumbnails everywhere else when I configure the galleries and albums etc.
This is with wordpress version 5.5.1 and NextGEN Gallery version 3.3.17