Just. Does. Not. Work.
It's an amazingly poorly written add-on where no one is able to use it properly. Not sure what are "MSI Developers" doing. For one, nothing shows up in the downloadable content list (it's always greyed out). Even when you do the stuff some enlightened person wrote in the reviews section (marking the pngs downloadable, for example), it now lists them, but still errors out and does not download them with the error "Unchecked lastError value: Error: filename must not be an absolute path" in the Browser Console. This shouldn't even be alpha.