(Drupal 8) Resolves 'missing required attribute' validation errors when using Lazy-load (lazy) module. Versions: lazy 3.6.0, lazysizes 5.3.1

mytheme.theme

<?php

/**
 * Implements hook_preprocess_image().
 *
 * Adding src here fixes validation error 'Element img is missing required
 * attribute src' when using the lazysizes library.
 * https://github.com/aFarkas/lazysizes/issues/500#issuecomment-616115829
 */
function MYTHEME_preprocess_image(array &$variables) {
  if (!isset($variables['attributes']['src'])) {
    $variables['attributes']['src'] = 'data:,1w';
  }
}


/**
 * Implements hook_preprocess_responsive_image().
 *
 * Adding srcset here fixes validation error 'Element source is missing required
 * attribute srcset' when using the lazysizes library.
 * https://github.com/aFarkas/lazysizes/issues/500#issuecomment-616115829
 */
function MYTHEME_preprocess_responsive_image(array &$variables) {
  foreach ($variables['sources'] as $k => $source_attributes) {
    if (!isset($source_attributes['srcset'])) {
      $variables['sources'][$k]['srcset'] = 'data:,1w';
    }
  }
}