1<div class="art-menu">
 2{%- for page in site.pages -%}
 3    {%- assign pagedir = page.dir | remove_first: "/" | split: "/" -%}
 4    {%- include pic-path.html -%}
 5    {%- if pagedir.first == "art" and pagedir.size > 1 -%}
 6    <div class="art-category">
 7        <a href="{{ page.url }}">
 8            {{ page.title }}
 9            <br>
10            <img src="{{ artpics.first }}">
11        </a> 
12    </div>
13    {% endif %}
14{%- endfor -%}
15</div>