That attachment originally came from this thread
in the IMP forum here at mobileread.com (and from me).
It really doesn't need to be re-posted here, unless of course, it's been updated.
That other program, ConvertIMP
, can extract/convert from .imp files to .html with images/styles. It was based somewhat on imp_dump, so should yield at least as good results, if not better.
Check it out, again!