I'm looking for a simple, efficient way to generate an HTML gallery from a hierarchy of jpeg images.

I.e. I have a directory ~/pictures which contains quite a deep hierarchy of sub-directories oranising my pictures organised as I want them. It's quite big, something like 30 thousand images which total something over 50Gb.

I want a way to generate a web gallery with much smaller iamage files (e.g. maximum image size something like 1024x1024) in a hierarchy with simple HTML (or whatever) to make it navigable with a web browser. This is 'all on one system', not for export to the WWW, it will just be displayed using the apache server on the same system.

I also want to be able to select just a few images and generate a gallery which will be possible to export to a web server. This is for showing people a few pictures by sending them a link in an E-Mail.

Currently I use Photofloat (https://git.zx2c4.com/PhotoFloat/about/) which does a fair amount of what I want but I'm looking for something better. Photofloat's disadvantages (for me) are:-

It puts all of its output in one directory, so for my whole hierarchy there are well over 100 thousand files in one directory. This makes some operations rather difficult and slow.

As a result of the above it's also difficult to find the reduced size version of any particular image which I sometimes want to do for attaching to E-Mails etc.

The navigation controls while adequate could be better.

It's not particularly easy to run Photofloat on a subset of my images, I've written a script to do it but the whole thing gets a bit messy.

So, any ideas for a relacement?