Non visible fields

I'm extending a Drupal 7 theme with a new template file to be called by a view.

Here my simple my template file, called views-view--agendas.tpl.php

<?php
   // /sites/all/themes/stability/stability_sub/templates/views-view--agenda.tpl.php
   dpm($fields);
   print $fields['field_images']->content;

The view is called like it should as I can see the dpm result with all the article fields in it. Here a dpm output extract

  ... (Array, 8 elements)
    title (Object) stdClass
    created (Object) stdClass
    path (Object) stdClass
    field_images (Object) stdClass
        handler (Object) views_handler_field_field
        inline (Boolean) FALSE
        element_type (String, 4 characters ) span
        content (String, 187 characters ) <img src="http://mde.local/sites/default/files/...
        raw (String, 3 characters ) 139
        class (String, 12 characters ) field-images
        inline_html (Integer) 0
        wrapper_prefix (String, 0 characters )
        wrapper_suffix (String, 0 characters )
        label (String, 0 characters )
        label_html (String, 0 characters )
    name (Object) stdClass
    comment_count (Object) stdClass
    body (Object) stdClass
    field_event_date (Object) stdClass

But for some reason, the second line display nothing.