I looked it up, and you can rip them with TexHaxU, with a BFLIM preset..BFLIMs are texture files for layouts ("binary cafe layout image"). I've been able to extract the images from some of them manually, but I don't think there's a converter for them yet.
http://gbatemp.net/threads/uwizard-all-in-one-wii-u-pc-program.386508/page-10#post-5495412