The main program principle is storing the links to the pictures, to be more specific, to picture files. Storing pictures separately makes it possible to copy them independently from program, to view them with third-party tools as well as to reduce the space needed to copy a link.
Pictures are arranged (gathered) into groups, and the group are arranged hierarchically as a tree, similar to folder tree in the Windows Explorer. Groups are displayed as folders in the left program window pane while the pictures contained in the group do so in the right pane.
Note that groups do not contain links to pictures themselves. These links are stored in a common list (containing links to all photo album pictures), items of which in turn store the following data:
- mandatory picture file name, that is unique to the photo album and cannot be used twice;
- optional picture date;
- optional name of the place;
- optional keyword list;
- optional picture description;
- optional film and frame number information;
- thumbnail (small scaled image) generated by the program automatically.
All these fields (except thumbnails) are searchable, ie can be found and selected later.
Groups are being filled from this common link list so groups contain "links to links to pictures". If that's still not clear, take a look to the picture:
What does it tell us about? It does tell us that picture once described in PhoA can be added to any (or even all) of the groups thus copying only link to it and keeping the actual link to the file (with appropriate description, date, place etc) only once.