This lets you define or modify default LightBox settings.

General preferences:

•Using the “Choose Application” button, you can choose which application you want to launch with a standard “Open File” dialog. 

Option  double click on a thumbnail and LightBox will tell your chosen application to open the selected file. If the specified application is not currently running, LightBox will launch it for you. (e.g.: Photoshop™ 2.0 or Canvas™ 3.0).