First off, thank you very much for this upgrade.

I like the updated lightboxes, as well as perceived performance increases.

Will it be possible in the future to easily incorporate additional box codes - i.e. Shadowbox, Ghostbox - which would make a video gallery a snap to implement?

Other comments so far:
1.  The option to turn off captions appears to do nothing - I have cleared the cache files multiple times, but the "Click here to open image!" remains.

2.  The plugin option to remove the navigation tip text from the popup is missing.

Whoops - I spoke too soon about the cache.  Clearing my browser cache seems to have gotten rid of the captions.

Switching to Slimbox2 got rid of the navigation help text, is the text perhaps hardcoded into Prettybox?

Thank you for the information.  I'm using slimbox2, which is doing it's job wonderfully.  The website we're using this for is a martial arts gym.  My fellow students have all commented on the excellent upgrade - everyone who has seen it is pretty happy with the new plugin.

Looking forward to see what else you have in store.  Good luck!