It just the usual nextgen album and gallery setup with matching wordpress pages (as far as I can remember). Instead of numerical ID’s in the shortcodes below I used text as that makes it a bit clearer (I hope).
On the nextgen gallery setup side I have.
Album: Gallery which contains
-> Album: Woodblock Prints
-> Album: Watercolours
Alubm: Woodblock Prints which contains
-> Gallery: Toshi Yoshida
-> Gallery: Takeji Asano
and so on.
Album: Watercolours which contains
-> Gallery: M Kano
-> Gallery: K Seki
and so on.
Then as wordpress pages I have.
Page: Gallery (top level) the use of page name Gallery is not in netxgen terms, its as in art gallery.
[album id=woodblock-album template=compact]
[album id=watercolour-album template=compact]
-> Page: Watercolours (second level)
[album id=watercolour-album template=compact]
–> Page: K Seki (third level)
[nggallery id=k-seki-gallery template=caption]
–> Page M Kano (third level)
[nggallery id=m-kano-gallery template=caption]
and so on for all the watercolour galleries.
-> Page: Woodblock Prints (second level)
[album id=woodblock-album template=compact]
–> Page: Benji Asada (third level)
[nggallery id=benji-asada-dallery template=caption]
–> Page: Hiyoshi Mamoru (third level)
[nggallery id=hiyoshi-mamoru-gallery template=caption]
and so on for all the woodblock print galleries.
On each wordpress page I add a div to center everything and album or gallery titles within h2 tags. Nextgen created all of the gallery pages I just tailored the content a little. I think I had to create the album pages (Gallery, Woodblock Prints and Watercolours). Then just used the wordpress Page Attributes Parent setting to order them hierarchically (maybe Nextgen did part of this?).
Hope this help.