I looked at the code. It isn't malicious, but it is overly complicated for what it actually does. It basically implements a very dumbed down version of Greasemonkey and then runs itself as a script in the page examining all web traffic on Amazon's site and replacing images with links to the Pirate Bay.
There's much simpler ways of doing what it does. --
I wanted to use something as an example that nobody would want to pay for. -- "Fascism should more properly be called corporatism because it is the merger of state and corporate power." -- Benito Mussolini