bug or intention?

I posted this in another forum section and have gotten no answers so my apologies for posting twice. I assumed at first this was by intention but now I'm wondering about unintentional problems. The same problem does exist in the responsive classic template.

I've been playing with the product info page V. 2.0 - moving elements around (working in the default classic green template). I kinda see what's going on and like the new pop ups. I want the additional images to be under the main image but when I put it there (leaving the originals at the bottom for reference), the images are visually larger than the originals at the bottom. (using demo images) Once the set was moved under the main image, the images showed as the same size as the bottom original set. In the source the images are width="100" height="80" which is correct for the actual image dimensions. Both sets are displayed larger than the actual sizes. The pop up images are even larger still. Um. What? (The product image shows with the correct dimensions.)

The elements are modalboxes/tpl_image.php and tpl_additional.php and stylesheet_image_modals.css and stylesheet_image_modals.php and jsript_image_modals.js and of course the tpl_modules_additional_images.php

But if I pull those elements and use a different zc version (updating the jquery version), nothing works at all so I must be missing something important.

I am thrilled that this is no longer the old fashioned popup but a new feature needs new guidance for template designers as well as some scrutiny on what is actually happening.

The problem is the image-grid. Removing that from the addtional images div fixed the display issue completely so definitely not a bug nor a oops.
The tpl_modules_additional_images.php file says :
* Plugins for older templates, such as colorbox etc, may need to use the old manual-grid display template
* In such case, set $use_legacy_additional_images_columnar_template=true so that the modal grid isn't generated
* You will also need to remove the 'class="image-grid"' markup in the <div> above.

It would be a big help if you updated the documentation:

https://docs.zen-cart.com/user/images/popups/

Did you not notice I withdrew from that? Did it ever occur to you to ask why?