Adding a background
A theme can put an image behind Discord’s interface. Add an optional background object to your theme definition with the image url, and tune how it sits behind the UI with blur and opacity.
{
type: 'midnight',
semantic: { /* ... */ },
raw: { /* ... */ },
background: {
url: 'https://example.com/wallpaper.png',
blur: 4,
opacity: 0.5,
},
}
Fields
The image to display behind the interface.
How much to blur the image. Higher values soften it so foreground text stays readable.
How visible the image is behind the UI, from 0 (hidden) to 1 (fully opaque).
A background competes with your text for legibility. Pair it with semantic colors that hold up over the image, and lean on blur and a lower opacity so the interface stays readable.
Make the surfaces above the background semi-transparent in your semantic colors so the image shows through. A fully opaque BACKGROUND_PRIMARY will hide it entirely. 
