wp-image-sizes

<?php

namespace heyjones\wp_image_sizes;

add_action( 'after_setup_theme', __NAMESPACE__ . '\\after_setup_theme' );

function after_setup_theme() {
  $sizes = array(
      'thumbnail' => array(
          'size_w' => 360,
          'size_h' => 360,
      ),
      'medium' => array(
          'size_w' => 720,
          'size_h' => 9999,
      ),
      'medium_large' => array(
          'size_w' => 1080,
          'size_h' => 9999,
      ),
      'large' => array(
          'size_w' => 1440,
          'size_h' => 9999,
      ),
  );
  foreach( $sizes as $size => $options ) {
      foreach( $options as $key => $val ) {
          $option = sprintf( '%s_%s', $size, $key );
          if( $val !== get_option( $option ) ) {
              update_option( $option, $val );
          }
      }
  }
}