Can you show a single image in text in a lightbox, or a modal?

Yes, you can - but you need the "Custom BS Module" to load the necessary Bootstrap component, based on choices made in the module options. So... even if the module is empty, it will load the Bootstrap, won't it?

If I put the -otherwise empty - BS Module somewhere inside the article, will it still work?
Yep! And I can put the image anywhere inside the article  I can even put a float on the triggering image and have the text continue right around it!

So what happens if I put the Modal itself right at the bottom of this article, and continue with the text right after the triggering image? Oh my goodness, yes, this text will show up right next to the image! Which means I can use this to make a clickable image in the text.

This is really nice! It means I can include nice clickable images right inside an article, how lovely!

It does need quite a bit of code in the article, though. Here the code added to the triggering image:

<!-- trigger modal -->
<p class="metfloat"><img src="/images/bootslider/tara-sm.jpg" loading="lazy" width="250" height="250" data-path="local-images:/bootslider/tara-sm.jpg" data-bs-toggle="modal" data-bs-target="#exampleModal" class="handje" /></p>

And here's the code for the modal:

<!-- Modal -->
<div class="modal fade" id="exampleModal" aria-labelledby="exampleModalLabel" aria-hidden="true" tabindex="-1">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="exampleModalLabel">Tara</h5>
<button type="button" class="btn-close" data-bs-dismiss="modal" aria-label="Close"></button></div>
<div class="modal-body">
<p><img src="/images/bootslider/tara-lg.jpg" loading="lazy" width="900" height="900" data-path="local-images:/bootslider/tara-lg.jpg" /></p>