WordPress restrict files bigger than 1mb

functions.php

/**
 *  Restrict files bigger than 1mb to all users expect the ones inside of the array 
 *  https://www.nuno-sarmento.com
 */
 
 add_filter( 'upload_size_limit', 'ns_change_upload_size' );
 function ns_change_upload_size(){

	 /* setup an array of user ids to not be affected */
	 $restrictupload = array( 1, 14, 17, 37, 14263, 14289 );

	 /* check whether the current user id exists in the above array */
	 if( !in_array( get_current_user_id(), $restrictupload ) ) {
     return 1000 * 1024;
   }

 }