This plugin is meant to provide an aesthetic background for the Editor view of Obsidian. It currently only supports remote assets, so you'll need to host your own images.
As part of the settings, there's additional tweaking that's available, like modifying the bluriness of the background, and the contrast of the input area.
I use animated gifs as my background, particularly ones by waneella.
This example uses no bluriness and default input area contrast.
This example uses high degree of bluriness, with no input area contrast.