Jekyllrb.com

Please put your images in subfolders under $jekyllroot/img/ e.g.

jekyllroot
|_ img
  |_ gallery
    |_ 2018
      |_ 01
        |_ 16
          |_ origami_festival
            |_ 01.jpg
            |_ 02.jpg
            |_ ...
            |_ 99.jpg

Jekyll runs Liquid templates and relies on Front Matter, which is represented by the first block in between the ---. And this is where the gallery’s path is set. The if-statement in the loop, looks like it doesn’t belong, but due to the nature of how Jekyll iterates and builds, we have to live with it.


---
layout: post
title: Origami Festival
tags: [album, paper]
gallery_path: "/img/gallery/2018/01/16/origami_festival/"
---

{% comment %} file: jekyllroot/_posts/2018-01-16-origami-festival.html {% endcomment %}
{% for image in site.static_files %}
  {% if image.path contains page.gallery_path %}
    <p><img src="{{ site.url }}{{ site.baseurl }}{{ image.path }}" alt=""></p>
  {% endif %}
{% endfor %}

You can of course turn this into an include or jekyll inclusion module, with a little more work.

Caution! Please adapt your code according to your settings in _config.yml of url and baseurl settings.