Many of our pictures are from a variety of social groups, events or reasons. So for organizing it as a directory folder not always makes a lot of sense, because of the overlap of the different situations; if you try to keep track for every category of the photo gou will end up with a lot of copies of it.
This is when it comes the tag organization for you to be allowed to add tags to every photo (maybe with an auto tag function) and in the gallery an option to display de photos grouped in an albumtag. So if you have a photo with your family, friends and your dog, you can find it in their respective albumtag along with other of the same type photos.
This should be done with a cache/lazy update so it doesn't have to recalculate every time the albumtags because it wil be online update and dynamic for every new tag in a picture it make it fast and more intelligent.
This will be a nice, clean and save space way to organize your photos, which every time gets bigger and bigger.
