I wanted to set my world's background/header to a preset image, but when I try, it gives me a message telling me it couldn't save because either my connection is down (nothing else causes this and my connection is stable on everything else), or an invalid character was used (impossible). I haven't tested it with a custom background. This happens on both devices/browsers I have tested- Firefox on Windows, and Samsung Internet on Android.

1. Attempt to change the world's background to a preset image.