Opening and Closing Directories in PHP?

[fastismatt]

I wrote a function to save uploaded picture files to a directory without using an open and close directory commands. It works absolutely fine on my computer. I also wrote a function to pass the picture through so that the actual picture directory isn't visible to users.

Will I need to use open and close directory commands on a server, or only if I use a folder outside of htdocs, or for any other reason? Also, does not closing a directory open up a portal for a hacker to retrieve or delete all images?

Thanks.