[PHP] protecting a directory by php mysql

[Ali Asghar Toraby Parizy]

Hi.
I need a protected directory in my server that only the authenticated user
can reach all files in that folder(file type is zip and picture or a web
page, maybe). I save user ID and passwords in mysql database. today I tried
to use htaccess but mod_auth_mysql isn't installed on my server.
I know that I can protect web pages by a simple PHP script(checking log in
session) but I don't know how I can protect images and files!
Thanks for any help
-- 
Ali Asghar Torabi