In jAlbum 12.7, if you use "fileiterator dirs" or "fileiterator nodirs", some variables are not calculated correctly. In particular, indexNum, indexPage and indexImageCount are unreliable if an index contains sub-folders and images.
In jAlbum 13, these problems are fixed. If you developed a custom technique to manage these variables, you may be able to remove your customization.
I discovered these changes while tweaking ExhibitPlus.