I just wanted to post a quick 'tutorial' for anyone who is interested in adding arrow-key navigation to this plugin. The Pro version from RayGun already has that functionality, but the free version was lacking it. I checked with Dalton at RayGun and he gave me the OK to post this as a tutorial but said that RayGun has no plans of adding it standard to the free version.
So, if you're interested in hacking this plugin to include arrow-key navigation the instructions follow.
*do not attempt this if you think you 'might break it.' this is not a hard modification to do by any means, but i take no responsibility if you 'break your site.'
To enable Arrow-Key navigation in Portfolio Slideshow:
1) Navigate to: Plugins -> Editor -> Portfolio Slideshow
2) Open portfolio-slideshow/inc/shortcode.php
3) Scroll to the bottom of the document, and just above the line that reads
add this code:
4) Enjoy flipping through the images in your galleries with the arrow keys on your keyboard.