currently the thumbnails to use: http://photobatch.stani.be/
It is very fast, and with multiple functions ... As with Piwigo, only list the pictures it takes more minutes .. 15 0
beyond that to start a process is also slow ...
I imagine it's because I have nearly 1,000,000 pictures and therefore the system becomes a little slow ...
This will hopefully be resolved later in future versions of Piwigo ...

The problem lies that my program crashes when you use today is an incomplete picture. and because I have to go to fix the problem manually ... Currently process large amounts of images.

I would appreciate if you know of any script .. by shell, or some other methodological, to the thumbnails. to do this recursively.