forcing a multi-threaded rebuild

I had to get off my hosting provider and didnt copy the cache down.
In order to avoid any new hosting limits I got my quad-core-2gb ubuntu running under the table, installed mysql/apache and the works and imported gallery.

Now I need to rebuild all resizes and thumbs, kicked of the process and its projected to finish in 2 months... For some reason it says there 33532 pictures, when in reality there are 16687.

Anyway, I noticed that if i just browser to album it kicks off up to 9 rebuilds/thubms as needed.
Is there any way to force this? Any tool to browse/open each photo 10-20 at a time? I have CPU/RAM to spare.

Thank you!