subcategories Code Error ??

i have that code for showing categories along with the description and category images
but i need to display only the subcategories for the current category
how can i modify that code ??

<ul>
 <?php foreach (get_categories() as $cat) : ?>
 <li>
 <img src="<?php echo z_taxonomy_image_url($cat->term_id); ?>" />
 <a href="<?php echo get_category_link($cat->term_id); ?>"><?php echo $cat->cat_name; ?></a>
 <div class=\"description\"><?php echo  $cat->description; ?></div>
 </li>
 <?php endforeach; ?>
</ul>