Done some digging, and altered the settings related to the thumbnail size in the library, edited the LibraryState.xml but poser ignore that, and if you set it to read only poser doesn't even check this file on first load up, but only access it on exit, which says to me that poser has the thumbnail sizes stored elsewhere. Is anyone else still having this problem?

Getting old and still making "art" without soiling myself, now that's success.