A cron-ready script for choosing a random wallpaper on a GNOME desktop. Some ideas borrowed from https://github.com/thedevsaddam/ubuntu-live-wallpaper and crontab.guru.

random-wallpaper.py

#!/usr/bin/python

# usage: random-wallpaper.py <directory>

from os import environ, listdir, system
from os.path import isfile, join
import random
import sys

environ['GIO_EXTRA_MODULES'] = '/usr/lib/x86_64-linux-gnu/gio/modules/'

# Scan directory
directory = sys.argv[1]
files = [f for f in listdir(directory) if isfile(join(directory, f))]

# Choose a file
chosen = random.choice(files)
filepath = join(directory, chosen)

print("Setting wallpaper: " + filepath)

# Update wallpaper
command = "gsettings set org.gnome.desktop.background picture-uri file:///{}".format(filepath)
system(command)