Add a hint on the media upload screen in admin (Wordpress)

functions.php

<?php

function upload_hint() {
  global $common_config;

  $adminscreen = get_current_screen();

  echo '<p>';
    _e('Consider uploading images of at least 1050 pixels in width.','site');
  echo '</p>';
  
  // when featured images serve as logos
  if ($adminscreen->id === 'post-type' && current_user_can('edit_users')) {
    echo '<p>';
    _e('It is recommended to upload the logo in SVG format for better quality.','site');
    echo '</p>';
  }
  
  if (!current_user_can('edit_users')) {
    echo '<p>';
      echo $common_config->svg_role_error_label;
    echo '</p>';
  }
}

add_action( 'post-upload-ui', 'upload_hint' );