Those files should be added only at page that actually use them. 
You can do something like:

```
{% block stylesheets %}
{{ parent() }}
{% if event.gallery is not null %}
    {% stylesheets
    'css/lightbox.css'
    'css/carousel.responsive.css'
    filter='cssrewrite' output='css/compiled/gallery.css' %}
    <link rel="stylesheet" href="{{ asset_url }}" />
    {% endstylesheets %}
{% endif %}
{% endblock %}
```

in ``KrakDevs:Event:display.html.twig``