Page with a gallery of thumbnails with the links to the sub-pages

practically, you can do like this:

add a custom field to each page, called thumb with value of thumbnail url.

In your gallery page (use custom page template), you can use query post to get a list of all pages. Then you can display thumbnail and link it to original page.

like this: https://benjacobsenphoto.com/gallery/
?

That’s just a normal page done in HTML then the links go to subpages with nextgen slideshows…

I dont think its nextgen, but yes, I mean something like this..

that’s my page, I’m telling you it’s an HTML page with a table and the images link to nextgen gallery pages. ??