I've never tried saving an IHG session,
but: sometimes IHG somehow "misses" the trigger to batch download images from a given post. In that scenario there's a couple of approaches I've used: a) just re-do the download, or b) select the first (or last) file in the download window queue, use the shift key and select all the other files (click last/first), then get IHG to restart the download.
Might that work?
