Expected behavior

If you want to customize the default avatar in WordPress from a plugin or theme, normally you'd do so via one of the avatar filters like so:

function example_custom_avatar_data($args, $id_or_email) {
  $args['default'] = 'https://placeimg.com/96/96/animals';
  return $args;
}

add_filter('pre_get_avatar_data', 'example_custom_avatar_data', 10, 2);

In which case any request for a Gravatar that does not exist will instead display our custom default image:

This functionality is helpful in cases where we want to extend WordPress's default avatar functionality dynamically via a plugin.

Actual behavior

In Timber, the following code in the context of a post comment…

<img src="{{comment.avatar}}" width="96" height="96" alt="">

…will never display the image path set via the filter using $args['default']. It will always fall back to get_option('avatar_default') unless $default is provided from the template.

Steps to reproduce behavior

1. Activate the Timber starter theme.
2. Add the Twig snippet above to the theme's templates/comment.twig.
3. Add the PHP snippet above to the theme's functions.php or to a new plugin.
4. Navigate to wp-admin/options-discussion.php and scroll to the "Default avatar" section. All default avatars should display the image path provided in the PHP snippet.
5. Navigate to a post containing comments with a default image visible. Observe that the image displayed does not match what was defined in the filter.

What version of WordPress, PHP and Timber are you using?

• WordPress 5.7.2
• PHP 7.4.1
• Timber 1.18.2

How did you install Timber? (for example, from GitHub, Composer/Packagist, WP.org?)

• WP.org, synced locally via Local