> Started another (action defaulted to Continue) and
> after a few seconds it started download all EXEs.
> All screenshots.jpg. All snap.gif.

Humm, so the steps were:
  * download the site entirely
  * start an update and quickly end
  * continued an update

In this case, the issue is different: the previous cache was lost, due to
missing code to merge the two caches.

The issue I spotted were content being re-downloaded when using --continue,
with not-interrupted sessions, so this is unrelated IMHO.

To allow session interruptions, without losing the previous cache, httrack
would have to merge the two caches in one.. I'll check if this is something
doable.