<?php
    $parent = get_cat_ID("photos");
    $cats = get_categories('child_of='.$parent);
	$term_id = get_query_var('cat');
	$image = get_option( 'taxonomy_image_' . $term_id );
    foreach ($cats as $cat) {
        echo "<ul>";
        echo sprintf("<li><a href='%s'><img src=".$image.">%s</a></li>", get_category_link($cat->term_id), apply_filters("get_term", $cat->name));
        echo "</ul>";
} ?>