Can you use a nswf as a background on your own xbox

You cannot use any such things, anywhere on Xbox

Yes, they are free, because they aren't actually themes. Instead they are just customizable backgrounds.

You can either use an achievement tile as your background, or insert your own background using the instructions here: http://majornelson.com/2014/10/22/heres-make-xbox-one-background/

Any j-peg that you can put on a flash drive can be used as your background theme pic.

I've been using my own pics for 6 years.

Hmm... you know what else its missing? A soundtrack in the background, something similar to the PlayStation 4 dashboard.

But Xbox can do better by perhaps having us customize our own wallpaper *AND* background music? OR even better?

Hi there the only way to get rid of it is to put a solid color as your background, it turns on when you use achievement art as a background. You can your background to a solid color by going to settings, my xbox. Hope this helps