I ended up on Piwigo. It’s pretty fully featured and allows you to set up access controls for groups. Also has client apps.

I don’t really understand this reply and why this is a shower thought.

But, I take it back. Clearly not a pastor or sermon. Sorry, my bad…

https://lemmy.world/pictrs/image/b6781fe4-3459-42bf-adce-b9e26f7078b1.jpeg

Is this one of those “how do you do fellow kids” accounts made by a very young looking , middle aged pastor attempting to infiltrate social media?

https://m.youtube.com/watch?v=C-q4bEULG64

These are fully stand alone. Downloadable. So not strictly hosted I guess?

Does it need to be “hosted”?

I like both these:

yEd (https://www.yworks.com/products/yed)

Dia Diagrams (http://dia-installer.de)

I think yEd had a free version but closed source.