A Juicebox gallery is still a Juicebox gallery, no matter what type of page it is embedded into.
The only difference is that the method of creating the gallery may not give you access to each and every Pro configuration option (and some manual modification may be required depending on how you go about creating and configuring your gallery).
However, upgrading the Juicebox module for Drupal from Juicebox-Lite (which it comes bundled with) to Juicebox-Pro will instantly lift the 50-image per gallery limit with no further action required.
How the module sources images, however, will be written into the module's code and might not be so easily changed.
Please note that we did not write the Drupal module ourselves and support for the module would be better directed towards the Drupal forum where the author of the module should be able to help you further.

With regard to the thumbnails in your gallery not displaying, the thumbURL entries in your gallery's XML file (http://dev.hmssurprise.org/juicebox/xml … 2eb25dc36a) are defined as follows:
http://dev.hmssurprise.org/sites/defaul … k=8jI9t1Iu
http://dev.hmssurprise.org/sites/defaul … k=QpRz8ipD

If I visit either of these URLs directly in a browser, I see an 'Error generating image.' message (rather than the image itself).
Searching through the Drupal forum with the term 'Error generating image.', it looks like the problem might be related to the permissions on your 'thumbnail' folder (or subfolders) or on the image files themselves.
Please check that the permissions are not too restrictive (using an FTP program) which may result in the images not being able to be read.
Default permissions of 755 for folders and 644 for images should be fine.