Using this simple script you can download Bing daily picture and set it as your background :)
NOTE: This script tested only on Gnome and Unity desktops!
git clone https://github.com/farbodgame/bing-downloader.git
cd bing-downloader/
sudo chmod +x bing-downloader.sh
./bing-downloader.sh
You can use crontab
to run script in special time.