The folder of Gallery Assist should be easy to understand.
A global gallery folder (gallery_assist) contains all galleries created through this module.
A gallery user folder (named after the UID of the user) contains the galleries belonging to that user.
The gallery presets folders are:
- img: contains mini thumbnails for the Gallery Assist pager
- thm: contains thumbnails of the gallery as long as Gallery Assist ImageCache is not installed
- prev: contains the preview images of the gallery as long as Gallery Assist ImageCache is not installed
Once Gallery Assist ImageCache is installed, Gallery Assist thumbnails and preview images are not longer produced by the Gallery Assist module. The ImageCache does it instead.