Timber + Twig srcset image partial

image-srcset.twig

{# Include in views like so: {% include 'partials/image-srcset.twig' with {image_id: post.get_field('hero_background_image'), class: 'hero__background'} %} #}
{# To print image object: {{post.get_field('hero_background_image')|print_r}} #}
<img class="{{class}}" alt="{{TimberImage(image_id).alt}}"
    src="{{ TimberImage(image_id).src('large') }}"
    srcset="{{ TimberImage(image_id).src('xlarge') }} {{ image_id['sizes']['xlarge-width'] }}w,
            {{ TimberImage(image_id).src('hero') }} {{ image_id['sizes']['hero-width'] }}w,
            {{ TimberImage(image_id).src('large') }} {{ image_id['sizes']['large-width'] }}w
" />

Based on work by Christopher Soder-Duncan