There is some problem with the image-gallery.js that comes in this gem.
I'm running Rails 3.2.11 and if I use bootstra-image-gallery.js from https://github.com/blueimp/Bootstrap-Image-Gallery everything works fine. Although if I use image-gallery.js from the gem the gallery doesn't show up.
Please patch this gem in your own fork, by substituting with the latest bpptstrap files from those
Plugins, then make a pull request when you have them working :)