b oy le,

Welcome to the forum!

Child pornography is among the most common topics on this forum. So why is it still a problem? There is no 'uploading' to prevent. As Peerless writes:

the materials are not on LimeWire, they are on the gnutella network....hosted by people who have them on their own computers and have chosen to share them...they might be using LW, BS, Phex, or any other gnutella client...

For more on this topic go here:
Underage Nudity Being Shared On The Gnutella Network - Porn and Laws ( 1 2 3 ... Last Page)

You'll see there's a lot you can do to prevent accidental downloading, and, if you're so inclined, ways to assist law enforcement.