How does the reply button change to img - wordpress comments

I create a comment system. How can I use an image instead of replay_text?

    comment_reply_link( array_merge( $args, array(
        'reply_text' => '<img src="assets/images/ui/replyarrow.png">',
        'add_below' => 'div-comment',
        'depth'     => $depth,
        'max_depth' => $args['max_depth'],
                                 

Thank you