A little child lover could be a little child who loves something or someone.
A little child lover could be someone little who loves a child.
A little child lover could be someone who loves only little children.

Similarly,

Child pornography could be pornography specifically for children.
Child pornography could be pornography specifically of children.
Child pornography could be one or more in a set of porno-graphs that is generated by an original porno-graph. This is a stretch, but imagine in Debbie Does Dallas, Debbie and John are getting off with each other as they watch something pornographic on their own television. The scene shows a short cut to what they are watching. This seems to be quite popular so the producer of Debbie Does Dallas creates a second movie showing what Debbie and John were watching. A "child" movie from Debbie Does Dallas.