Firstly, I have this view on table:

when I click the td, it opens the PrettyPhoto Lightbox
on prettyPhoto, the default html trigger is:
<a href="images/fullscreen/2.jpg" rel="prettyPhoto" title="This is the description">
<img src="images/thumbnails/t_2.jpg" width="60" height="60" alt="This is the title" />
</a>
but instead I have this html:
<a href="image.jpeg" data-rel="prettyPhoto" rel="prettyPhoto[pp_gal]" class="kt-user-card-v2">
<div class="kt-user-card-v2__pic">
<img src="http://wasapbro-2019.test/storage/msg/cupb1RUgcGLnUovQi7eBpxLIIRu37sPKcha1jjuI.jpeg" class="m-img-rounded kt-marginless" alt="photo">
</div>
<div class="kt-user-card-v2__details">
<span class="kt-user-card-v2__name">test</span>
</div>
</a>
on mine that fails to trigger
How do I solve this?
I am not sure how you are initializing PrettyPhoto, but I set up this quick demo using your DOM structure and it seems to work just fine. One thing to note is that you need to use jQuery version 2.x or older since PrettyPhoto relies on .size(); which isn't available in jQuery 3.0+.