Methods for image gallery+captions, flexbox vs gridbox

The best solution, since your previous thread had more or less received a complete response, is to start a new one... :)
That's what I did for you... Here is the response I was going to post when the forum was replaced and the latest messages were deleted... 

so… no worries at all, curiosity is a good sign 🙂

About flex: 1 1 0: the short version is that it tells Flexbox that all items can grow, can shrink, and start from the same base size, so they share the available space evenly. Rather than going too deep here, I’d really recommend this reference, it’s one of the clearest and most complete explanations out there:
https://css-tricks.com/snippets/css/a-guide-to-flexbox/

It’s very well written and much more explicit than many video courses.

Feel free to come back with questions as often as you like.

The only small suggestion I’d make is to open a new thread when you switch to a new question. It makes things easier to follow, and also helps other readers who might land on the thread later, instead of having one very long, mixed discussion.

Regarding the JavaScript part: in the example we discussed, JavaScript was only there because a selector was used to change the number of images interactively. In a “normal” page, without any selector, the logic would be different. You’d typically run the script on page load and simply count how many img elements are inside the figure. We can look at that setup separately (on a different thread) if you need, and when you’re ready.

One important clarification as well: we’re talking about JavaScript, not Java. They are completely different languages, despite the similar names.

If you’re looking for reliable starting points, I wrote an article that maps out the main web languages and learning resources here:
https://www.puce-et-media.com/le-parcours-du-developpeur-web-guide-des-langages-et-ressources-fiables/

And Birnou wrote a complementary one about setting up a clean working environment with VS Code and Dreamweaver side by side, which can really help when learning:
https://www.puce-et-media.com/preparer-son-environnement-de-developpement-vs-code-et-dreamweaver-cote-a-cote/

Take your time with it, and don’t hesitate to ask when things start to feel fuzzy. That’s usually where the real learning happens.

And when you move on to a new topic, opening a new thread would really help keep things clear and easy to follow. If a moderator feels it makes sense to split or create a dedicated thread, that could be helpful as well.