make directory

[Jolten]

Hi,

I'm looking for something that can check to see if a directory exists titled $bbuserinfo['username'] and if not create a directory named $bbuserinfo['username'] after the currently browsing user.

I'm okay with php but I've never worked with directories before. At least not creating them. I'm reviewing php.net on it but if someone could give me some helpful tips I'd appreciate it.

The directories will simply store images.