If statement within PHP echo

According to the plugins documentation (http://zahlan.net/blog/2012/06/categories-images/), this seems pretty simple:

<ul>
<?php 
$categories = get_categories( $args );
foreach ( $categories as $category ) {
    $img_src = z_taxonomy_image_url($category->term_id);
    if ( $img_src ) {
        echo '<li><img src="' . $img_src . '" alt="" /><a href="' . get_category_link($category->term_id) . '" rel="bookmark">' . $category->name . ' - ' . $category->description . '</a></li>';
    } else {
        echo '<li><a href="' . get_category_link($category->term_id) . '" rel="bookmark">' . $category->name . ' - ' . $category->description . '</a></li>';
    }
}
?>
</ul>