Function to export bytea data from database to a directory

Hi
The following function import Images to the database however I wan reverse
of it i.e. taking the image out to a directory, I tried to reverse but can
not get it right, can some be kind enough to do that for me !!
Many thanks
Terry

[code]

create or replace function bytea_import(p_path text, p_result out bytea)
language plpgsql as $$
declare
l_oid oid;
r record;
begin
p_result := '';
select lo_import(p_path) into l_oid;
for r in ( select data
from pg_largeobject
where loid = l_oid
order by pageno ) loop
p_result = p_result || r.data;
end loop;
perform lo_unlink(l_oid);
end;$$;
[/code]