"Warning : Can't currently handle huge JPEG 2000 boxes" when it encounters such a box but otherwise reads out no information from it.
I tried out the sample JP2 image mentioned in the forum post(http://www.loc.gov/ndnp/guidelines/examples.html) with FITS and it reports neither the
warning or the metadata in the image. According to the forum post, Phil Harvey will add support for the huge JP2 box format in the next version of Exiftool, 10.03.
Perhaps an update of the tools included in FITS is in order?
Best,
Tom