I guess I did decide to work on this a bit more.
Changelog:
- The images in the uploaded files are now preloaded, which means they immediately appear with the rest of an uploaded file in the UI.
- Uploads are now delayed by the server rather than rejected with a 503 when it's cleaning up
- The available disk space on the server is now checked on startup, and it can be configured to stop if there isn't enough
- Also added the npm packages to the credits