My suggestion is could there be a third option (Reference 1:3 in manual) of importing not only from Posts Categories and NexGen galleries but also from Excel spreadsheet range
e.g. Sheet1!$A$61:$C$74 into a directory say "Manufacturing"
Column A sub directory Column B (subdirectory) Column C (subdirectory) Column D etc etc
(All manufacturers starting with Letter ' ') (Manufacturer) (category of Photo of vehicles) (car series)
A Alfa Romeo Model car Guilia
A Alfa Romeo Real Car Guilia
B Bugatti Model Car Type 101
B Bugatti Real Car Type 101
This will make the setting up of a large directory much quicker but accept the fact that plugin is excellent for a 'evolving' website but not so much for large more complicated structured ecommerce database that needs to be setup at the start of developing a website.
Maybe a possible future enhancement?
Anyway I happy enough with the plugin - the best I could find for my requirements.