KevinTheJedi
As promised, here's an update.
The footer seems to be sticking now, which is great news. The file key entry remains in the file table, but there's nothing in the chunks table. Not sure if that's an issue or not given it's currently working.
The only thing I did different was I uploaded the image from the root of the website on a browser on the host machine, instead of from my network machine. Not sure if that makes a difference or not.
Either way, it seems to be working. I'll come back if the issue returns 🙂