Building a site with pages that won't appear in menu bar. What do you do.

I have been thru all/most of the HTML oriented lessons and, am not sure what you do with specific types of pages.

I would like to have a site that when you click on a graphic, it opens up onto its own page. So that page won't actually be accessible unless the graphic is clicked on. Meaning it won't be in a menu area .

I am unsure if I make an .html file for each of these pages, or create a template and then use javascript to put in the graphics and text.

The idea would be for a portfolio site, to open some design work, and then have an explanation that could be several paragraphs long.

I have used some basic services before where you drag and drop to create a site and, I ended up with lots of pages but am unsure of what the best practice is.

If it is still unclear what I am going for please let me know and I will try to reword it. It makes sense to me because I know what I'm trying to find out. Thanks.