Does CI not have delete file functionality?

[eluser]zulubanslee[/eluser]
I'm trying to delete an image file from a directory. I tried using 'unlink' but I get an error message that says 'curl does not allow unlinking'. All the research I've done indicates that I have a files permission problem. So what should the file permissions be, and how do I change them to what i need them to be in order to delete it?

Can CI handle this for me or what?

Thanks for your assistance.