Laravel Scout and algolia ... index complex related models

Hi guys. Im testing argolia on my laravel projetct.
I have some complex model relationships. For example my Post table has a lot of belongsTo , hasOne and hasMany functions.
I need to index data from those related tables, so I had to overwrite the toSearchableArray method in my Post model:

public function toSearchableArray()

   $array = $this->toArray();
   $array['category'] = $this->category;
   $array['city'] = $this->city;
   $array['pictures'] = $this->pictures;
   return $array;

category and city tables are ‘belongsTo’ relations and data is properly indexed when creating a register but I can not make it work with pictures wich is a ‘hasMany’ relation.
When looking at the index, the pictures array is empty, however after running the
php artisan scout:import "App\Models\Post"
The image field is properly updated in the algolia index.
Is there some way to fix this ? Do you know why does it happen?
Any idea would be wellcome.

this is pictures function:

public function pictures()
        return $this->hasMany(Picture::class, 'post_id')->orderBy('position')->orderByDesc('id');