Image File System Question

hi,

My server is Postgres 8.0.1 on fedora core2.
My clients are remote and interface with my server using .NET GUI.

We are trying to store many images/icons/audio/video clips in our system.
We expect many of these. The way we are doing it is using Hierarchical File
System.

I understand we need to limit the size of these directories by controlling
number of resources in each directory.

The way i want to let anone access these resources is only through stored
procedures rather than direct downloading.
I am trying to create stored procedure/function API for the same. These
functions will check for the permissions for the user and/or the file,
check the location from the schema and then would "stream" it out for the
GUI to use.

The question is:
(1) How do i use the database stored procedures/functions as a tunnel for
just streaming the data rather than storing it in database?
That is, a function that given a Image ID for example, will read the
location from the table and then just go to the location and stream out the
bits.
(2) Am i right in saying that it can't solely be done iwth plpgsql but would
need somem c/c++ api.
(3) Has anyone here done something like this and can share with me how
he/she implemented this.

I did do my homework of googling for something like this but may be my
search skills were not strong enough to find some substantial
information/HOW TOs or examples.

thanks,
vish
(vishal saberwal)