Sorry for bumping a bit older thread but I'm experiencing the same thing?
I started mirroring a site but then cancelled it as I didn't want it to fully
download at that time and wanted to resume it later.
The html pages that were previously downloaded had the images in place (exact
copy). But when I resume the interrupted download and open the pages that were
ok aren't ok anymore now. The hmtl pages are there (and not redownloaded) but
the images are missing?Once the download finishes I expect they will be back
but why do they dissapear even though they were there before?
I also have update hack turned on and tolerant turned off (standard).

Thanks for any thoughts & help!