Great job on this. Just what the doctor ordered. I found a small code fix however in the plugin_jw_sig.php file that will keep the title (alt) text that shows when you hover your mouse over the thumbnail from showing the html code i.e. "You are browsing images from the article:Article Title.
It does it on the demo site also.
Just change this part of the code:
$html .= ' IE7 and Firefox.
Anyway, as I said before I love the flexibility of this plugin and I think it's a must have if you have any type of picture gallery in Joomla. Great Job!