How to display subcategory images on category page

<?php
$image_options = array('default' => true,'forcesize' => $this->config->get('image_force_size', true),'scale' => $this->config->get('image_scale_mode', 'inside'));

$img = $this->image->getThumbnail(@$this->row->file_path, array('width' => $this->image->main_thumbnail_x, 'height' => $this->image->main_thumbnail_y), $image_options);
                            
if($img->success) 
{
    echo '<img class="hikashop_product_listing_image" title="'.$this->escape(@$this->row->file_name).'" alt="'.$this->escape(@$this->row->file_name).'" src="'.$img->url.'" width="60px" height="35px" />';
}
                            
/*
echo $child->category_name;

if($this->params->get('number_of_products',0))
{
    echo ' ('.$child->number_of_products.')';
}
*/
?>