We had a use case where an image field needed to be used as a background image in the scope of page.html.twig. This is pretty simple with the use of template_preprocess_page().
To get the image field into the page variable use this code:
/**
* Implements template_preprocess_page().
*/
function MYTHEME_preprocess_page(&$variables) {
if (isset($variables['node'])) {
$variables['page']['image_in_page'] = $variables['node']->field_image->view();
}
}
Then, print the image in page.html.twig with:
{{ page.image_in_page }}
The logic above isn't checking whether the field_image exists, but should get you close.
Thanks for the assist: https://www.computerminds.co.uk/articles/rendering-drupal-8-fields-righ…