<?php
// options
// array(
//     'rtl'            => is_rtl(),
//     'animation'      => 'slide',
//     'smoothHeight'   => true,
//     'directionNav'   => false,
//     'controlNav'     => 'thumbnails', // can be boolean
//     'slideshow'      => false,
//     'animationSpeed' => 500,
//     'animationLoop'  => false, // Breaks photoswipe pagination if true.
//     'allowOneSlide'  => false,
// )
    
add_filter( 'woocommerce_single_product_carousel_options', 'update_woo_flexslider_options' );

function update_woo_flexslider_options( $options ) {
    $options['controlNav'] = true;
    return $options;
}