static_html_cache plugin has some interesting settings.
Could it be possible, when we edit an existing page, album, picture, to erase the corresponding html cache file when we submit the changes ?
Displaying the image, album, page will generate the (updated) cache file.
With this behavior, the cache expiry setting could be very high !
Probably no need to erase it anymore.

Could it be possible, when we edit an existing page, album, picture, to erase the corresponding html cache file when we submit the changes ?

We don't have that on purpose as you might have pages where related parts are shown, e.g. homepage with latest news/images etc. that would be outdated.

It is actually common practice to automatically renew the cache files via time setting. The more changes on your site the lower the expire time should be.

ZP is pretty fast so you might not even need a cache. Our site for example does not even use it currently.

I understand your comments.
I often disable the static cache and yes, Zenphoto is very fast.
I will probably keep it disabled.