Here is a little script I wrote to easily change the background-wallpaper.

I use this as I have to set a certain wallpaper before doing webinars or screencasts for my clients.

// Menu: Change Wallpaper
// Description: Change your background wallpaper by selecting from a configured folder.
// Author: David Losert
// Twitter: @david_losert
import "@johnlindquist/kit"
// Set to the folder where you keep all your wallpapers for easy selection
const wallpapersPath = await env('WALLPAPER_PATH');
const availableWallpapers = ls(wallpapersPath);
const selectedWallpaper = await arg('select', availableWallpapers.map(image => {
const imagePath = path.resolve(wallpapersPath, image);
return {
name: image,
preview: `<img src="${imagePath}">`,
value: imagePath
};
}));
await applescript(`tell application "Finder" to set desktop picture to POSIX file "${selectedWallpaper}"`);