There is a wonderful lightbox2-rails gem, but I can’t display the caption of the thumbnail, has anyone come across it?

Question

Ruby on Rails

https://github.com/gavinkflam/lightbox2-rails

<%= link_to image_tag(image_gallery.image_gallery_url.to_s, :size => "173x150",title: "#{image_gallery.title}", alt: "#{image_gallery.alt}"),image_gallery.image_gallery_url.to_s,title: "#{image_gallery.title}", :rel => "lightbox[#{gallery_name}]"%>

The modal window is very beautiful, it contains a scroll and a title, but I can’t get the caption on the thumbnail.
Although I will most likely add my own css. But if anyone knows how, I will be very happy. Since clogging the code is generally not very cool.