I found that converting the free Lone Wolf Gamebooks the "larger" images don't make it to the .LRF.
Seems to be a Calibre error because the htmls are perfect in firefox and are "simple".
Have tried using Calibre GUI and html2lrf.exe but everytime the same result.
Anyone care to have a go?
Download zip from this page
http://www.projectaon.org/en/Main/FlightFromTheDark