I might be a bit late with these but perhaps they can be "forward ported".  They involve plugin version 1.2.1...

SIG was breaking mod_sec by having "../../../" in the showthumbs path and frankly it was a (minor) security hazzard anyway.  I've modfied the code to use a root folder.

Also I've added a param to allow root folders other than image/stories (eg media/user)... 

The files as well as the diffs are supplied so perhaps they may be of use...

Bummer, there's an issue with this if you have a centralised J! installation that your sites symlink too on a linux system...I guess I'll look at the new version!