Hi marko,
thanks a lot for the very detailed instructions. There was a lot to learn reading them. I personally don't go to such a depth for the time being as most of my images are simply downloaded from the internet (about 25'000) or photos received from family and friends.
I am a very visual person (much more than audio) and like to collect and watch image slide shows all the time, but take very few pictures myself. The little editing I do is cropping edges. But I definitely like the stack concept.
The database structure I use is very similar. I was just wondering why you introduced a field "subject". I use "genre" and a user field "subgenre" for that. Genre is the standard field, while subgenre is a list field.
If you keep genre unique, it works very well. At the beginning I also had genre as a list field (named genres), but found it rather confusing having 2 list fields as a hierarchy and I wanted to have some specific hierarchy.
This is my top level genre list (in brackets some examples of subgenres):
Animals (Birds, Butterflies, Cats, Dogs, Elephants, Horses, Polar Life, Tropical Fish, Wild cats, Wild Life, Whales)
Animations
Architecture (Amusement Parks, Bridges, Canal&Dams, Castles, Churches&Cathedrals, Cityscapes, Covered Bridges, Harbour&Ports, Historical Buildings, Historical Places, Homes&Cottages, Lighthouses, Monuments&Memorials, Pyramids, Ruins, Sightseeings, Skyscrapers, Temples&Holy Places, Town&Villages, Watermills, Windmills)
Arts (from Gothic Art, Renaissance Art, Classical Age, Impressionism, Cubism to Modern Art, 16000 picturews altogether)
CD Labels
ClickArt
Entertainment (Aphorism, Dancing, Fireworks, Folklore&Traditions, Hot Air Ballons, Leisure)
Events (Birthdays; Jubilees, Parties; Vacation; Celebrations, Journeys, Outings)
Fantasy&Magic
Flowers&Gardens (all kind of flowers including Japanese Gardens, Natural Gardens, Wild flowers)
Graphic Arts
Holidays (Christmas, New Year, Eastern; Halloween)
Nature (38 different subjects)
People (Family&Friends; Celebs; Historic; Folklore)
Science-Fiction (Startrek, Babylon 5 etc)
Space (Planets&Moons, Space Travel; Deep Space, Clouds, Satellite Images)
Sports (all kind of sports)
Technology
Travel (Planes, Roads, Ships, Trains, Cars)
Altogether: 154 subgenres.
Most images are also tagged by continent, country and places. For the US I use the state as a country (US Alabama etc.). Places is usually a city or region.