You tried to {{ action }} {{ fs.attempted_iids|length }}
image{{ fs.attempted_iids|pluralize}} from a fileset,
leaving {{ fs.blocking_iids|length }}.
{% with MAX_SHOWN=4 %}
{% for iid in fs.attempted_iids|slice:":4" %}
{% endfor %}
{% if fs.attempted_iids|length > MAX_SHOWN %}
...
{% endif %}
{% for iid in fs.blocking_iids|slice:":4" %}
{% endfor %}
{% if fs.blocking_iids|length > MAX_SHOWN %}
...
{% endif %}
{% endwith %}
{% endfor %}