{% if book.is_picture %}
{% if book.image_file %}
{% thumbnail book.image_file "170x240" crop="center" as im %}
- <img src="{{ im.url }}" width="{{ im.x }}" height="{{ im.y }}" />
+ <img src="{{ im.url }}"
+ srcset="{{ im.url }} 1x, {{ im.url|resolution:"2x" }} 2x"
+ width="{{ im.x }}" height="{{ im.y }}" />
{% endthumbnail %}
{% endif %}
{% else %}