As long as Lightsail doesn't limit the capabilities of their VPS, I don't see why it would be any different from a normal install on Ubuntu.
yeah, it's identical. LightSail ends up being exactly like a DO or Vultr.
NodeBB image uploader comes from a plugin or is it a core feature? I can't seem to find it. I want to use a small vanilla js script to add a lightbox to uploaded images. I could add a class dinamically with js, I guess but I'd rather add it to the image output.
I don't know how to do it in another way.
It's a plugin, and you can use more than one.