Field plugin: Execute property query

1

I am trying to create a field plugin that displays an image using a passed path property as the src:

photo:
  label: Photo
  type: thumb // the custom field
  path: page('products').findBy('id', page.items.toStructure.first.id).thumb

Kirby::plugin('alex/thumb', [
  'fields' => [
    'thumb' => [
      'props' => [
        'label' => function($label) {
            return $label;
        },
        'path' => function($path) {
          return $path; // How can I execute this?
        },
      ]
    ]
  ]
]);

panel.plugin('alex/thumb', {
  fields: {
    thumb: {
      props: {
        label: String,
        path: String
      },
      template: `
        <div>
          <k-headline>{{ label }}</k-headline>
          <k-image src="{{ path }}" />
        </div>
      `
    }
  }
});

How can I get the result of the path query, instead of getting it as text?