hey cool. i have the same problem now.
the thing is, the image i want is in my theme directory. i tried using <?php bloginfo(stylesheet_directory); ?> inside <?php comments_popup_link…> like this:
<?php comments_popup_link(‘<img src=”<?php bloginfo(stylesheet_directory); ?>/icons/comments.png”>, (and so on…)
but it doesn’t work. any ideas? ??