Thumbnails are not generated

Omeka S Installing
4

I was having a look to the configuration options on the Omeka S user manual.
This might have something to do with the paths.
My local.config.php file have the default settings:

'service_manager' => [
    'aliases' => [
        'Omeka\File\Store' => 'Omeka\File\Store\Local',
        'Omeka\File\Thumbnailer' => 'Omeka\File\Thumbnailer\ImageMagick',

What should I change for?

I tried:

        'Omeka\File\Thumbnailer' => '/usr/bin',

But I get an error.

With Omeka Classic installation the path /usr/bin for imagick works fine.