OK - here's what I did (and it works great!)
for the sql statement I mentioned above - the one previously altered with the "paging in comments" MOD - I simply added
u.userpic
immediately after
c.comment_ip,
so it now looks like this
$sql = "SELECT c.comment_id, c.image_id, c.user_id, c.user_name AS comment_user_name, c.comment_headline, c.comment_text, c.comment_ip, u.userpic, c.comment_date".get_user_table_field(", u.", "user_level").get_user_table_field(", u.", "user_name").get_user_table_field(", u.", "user_email").get_user_table_field(", u.", "user_showemail").get_user_table_field(", u.", "user_invisible").get_user_table_field(", u.", "user_joindate").get_user_table_field(", u.", "user_lastaction").get_user_table_field(", u.", "user_comments").get_user_table_field(", u.", "user_homepage").get_user_table_field(", u.", "user_icq").$additional_sql."
basically, the only thing added to the sql statement is the "u.userpic, " part - which can be added anywhere inside that blurb. MAKE SURE YOU MATCH THE "," SEQUENCE ALREADY PRESENT. If you manage that, you're good to go.
for use in header.html, I'll mess with it - - unless someone else jumps in first.
many thanks again - this is easier (I think, anyway) to implement than the avatar MOD - and works just as well.