views/edd/shortcode-download-image.twig
{% set width = content_width // columns %}
{% set height = width // 1.618 %}
<a class="download-featured-image" href="{{ post.link }}">
{% if post.thumbnail %}
<img src="{{ fn( 'esc_url', post.thumbnail.src|resize( width, height ) ) }}">
{% else %}
<img src="{{ fn( 'esc_url', default_image.src|resize( width, height, 'center' ) ) }}">
{% endif %}
</a>