You can save the current file list as a stand alone "catalog" file. Information included in the catalog files are list ordering, general file info, icon and preview data, comments, and keywords. Once a catalog has been created, displaying previews and icons will be faster than accessing each image(i.e. in non-catalog mode).
An area of concern is the size of the catalog file. The major factor in this, is the size of the preview data. You can control this, by altering the size and depth of the previews(Preferences/Previews & Icons). If you have plenty of disk space, this is no problem, otherwise this can be a concern.
Opening a catalog file, is similar to opening images "on the fly", however, access to catalog data goes through the catalog file rather than the image file. This gives you quick access to viewing data(e.g. previews in list views). If you access the true image data, the file is required. In general, the catalog feature is intended to allow pre-made viewing info, that doesn't require the actual file to be present, until you need it(i.e. view the image fully).
You can add files to the catalog via Drag&Drop, or by choosing List/Add. Also, files can be removed using List/Remove.
