Q:

How do I bulk update the alt and title tags of images

Is there a way to bulk update image title and alt tags? Where do alt and title tags are saved in the database?

A:

Rewriting the D7 code of How to bulk update image alt and title?
$nodes = \Drupal::entityTypeManager()
  ->getStorage('node')
  ->loadByProperties(['type' => 'article']);

foreach ($nodes as $node) {
  $node->field_image->alt = $alt;
  $node->field_image->title = $title;

  $node->save();
}

