Putting files into folders according to type

Somewhere in one of the config files, I thought I saw something where you could restrict certain directories to certain types of files. Of course, I can't find it again. Am I imagining things?

I'd like to be able to restrict a folder called "Photos" to image files, etc. Can this be done, or did I imagine it?

I have PirateBox running successfully on a Raspberry Pi 3 and am in the stages of customizing it for an event I will be setting it up for.

Thanks.