You can initialize the lighbox using any
<img> elements. The first image on this page is a simple
<img id="first-image" class="img-thumbnail" src="./images/first/full.png" alt="" >
If you don't want to load the full image but a small thumbnail (when the lightbox is not opened) you can set
data-image-opened attribute. It will be the path to the image that will be opened in the lightbox.