CNSoft keeps changing the encryption for the pigg files because they don't want us opening and reading them. In fact, they added a stipulation to the EULA that says we won't try to read the pigg files any more. You won't be able to get the images unless your version of the pigg reader is newer than the latest encryption change. This is why we haven't been creating a lot of new mods over the past few years; we're technically limited to altering what materials we already have or what we can guess.
You shouldn't have much trouble making a cartoon from screenshots, though. Just open your screenshots in a normal graphics editor. I've done this before.
Check out "Hu's On Your Task Force?" at my blog.