And the plugin doesn't have any options that I can select to customize the gallery.
WP-Juicebox allows you to configure a Juicebox gallery using any or all of the configuration options available here.
All Lite options have individual controls within the plugin's interface and Pro options can be entered into the Pro Options text area, one per line, in the form optionName="optionValue".
How do I get the desktop application Juicebox Builder Pro galleries, into my wordpress site easily?
If you have created a gallery with JuiceboxBuilder-Pro and want to embed it into a WordPress post, then you could either:
(1) Recreate the gallery using WP-Juicebox and copy and paste the options from the gallery's XML file into the Pro Options text area.
... or:
(2) Do not use WP-Juicebox and, instead, use the baseUrl method of embedding as documented here.
Essentially, you would create a Juicebox-Pro gallery on your computer with JuiceboxBuilder-Pro, upload the complete gallery folder (not just the contents) to your web server and paste the baseUrl embedding code into the body of your WordPress post making sure that the method of entry is 'Text' rather than 'Visual'.
It does not matter where on your web server you upload your gallery folder to as long as the two paths within the embedding code (the path to the 'juicebox.js' file and the baseUrl itself, pointing towards the gallery folder) are correct.