{% set range = range(1, 47)|shuffle|slice(0,4) %}

<ul class="last-year-photos">
    {% for i in range %}
    <li class="last-year-photos__item">
        <picture class="last-year-photos__picture">
            {# For assets caching reason use year prefix for image files, e.g. "2018-1@1x.jpg" #}
            {#TODO: Add WEBP sources #}
            {#<source srcset="{{ ('photos/2018-' ~ i ~ '@1x.webp')|media }} 1x, {{ ('photos/2018-' ~ i ~ '@2x.webp')|media }} 2x" type="image/webp">#}
            <img class="last-year-photos__image" src="{{ ('photos/2019-' ~ i ~ '@1x.jpg')|media }}" srcset="{{ ('photos/2019-' ~ i ~ '@2x.jpg')|media }} 2x" alt="Random photo from last year conference">
        </picture>
    </li>
    {% endfor %}
</ul>