Basically, a category is represented by a directory at any level in PhpWebGallery directory galleries. If your website is not local to your computer, you will have to use a FTP client to manage your categories directory, otherwise you can create/move/delete directories locally. PhpWebGallery does not create directories for categories in galleries.

Each category can contain as many child-levels as you wish.

Warning : thumbnail, pwg_high, pwg_representatives are reserved directory names for PhpWebGallery. Don't use them for your categories.

Warning : the name of directories and files must be composed of letters, figures, ”-”, “_” or ”.” : {[a-zA-Z][0-9]-_.}. No blank space, no accentuated characters. This restriction is necessary because some web browsers does not support non ASCII or blank characters in filenames to display (pictures for instance).

PhpWebGallery proposes you to create virtual categories : no directory coresponds to this category. You can create virtual categories in screen [administration panel » Categories » Manage].

This feature is interesting only because PhpWebGallery offers you the possibility to associate an element to other categories than its storage category, as described in Elements management.

Virtual categories are represented the same way in public part of your site. So that users can't know if they are in a real categoroy or a virtual one. But who cares ?

A way to distinguish categories is about their content :

• daughter category : contains elements
• mother category : contains child categories

By the way, a category containing nothing should be an opportunity to have a deep reflexion about the way you organize your pictures .

Even if PhpWebGallery has no problem to manage categories that are mother and daughter at the same time, you are strongly advised for each category to choose between mother or daughter type. Here follows the design reasons that lead to this advise :

• Navigation : in the public part of the site, you may have understood that thumbnails of the main page can represent either a child category or an element. If a category contain at least one element, only thumbnails representing elements will be shown… and not thumbnails representing child categories. Having a category mother and daughter at the same time breaks the navigation when gallery members use only thumbnails to go deeper in your categories structure.

• Permissions : as explained in Album Permission Status, if you set a private category authorized for a user, automagically all parent categories of this category become authorized. If any of these parent categories contains elements, these elements will be reachable to the user. This may not be what you really want.

Another way to distinguish categories is the following :

• event category : the category is associated to an event like an anniversary, or a Christmas night.

• theme category : the category is associated to a theme like a person or a color

The advise is to organize your directories (so we are talking about real categories, contrary to virtual categories) by events and not by themes. Virtual categories will be dedicated to themes (they were made for this).