gistfile1.txt

{% for pair in article.featuredimage.split(',') %}
{% set parilist = loop.cycle(pair.split(':')) %}
        <li>
            <img src="{{ASSETSURL}}/media/photos/{{pairlist[0]}}" alt="{{article.title}}">
            <p class="caption">{{pairlist[1]}}</p>  
        </li>

{% endfor %}