How to concatenate image data in Postgres to use in fast report

How to concatenate image data in Postgres to use in fast report

Define your own aggregate to do binary concatenation and use it sql. 
eg.
CREATE AGGREGATE bytea_add(bytea)
(
    sfunc = byteacat,
    stype = bytea,
    initcond = E''
);
select bytea_add(logoimage) from emplimage where recordid=:recordid