I need to know whether or not using either Limewire or the Gnutella servers = can people put images/music on my server, or can they only download what I have on there?

In other words, is Limewire and Gnutella only for bandwidth and sharing, or are people actually going to start storing images and files on my computer? I want to make 100% people can't put files/images on my computer before I start using these programs.

A quick response would be appreciated!

Thanks.
P.J.