Wally
Change OSX Wallpaper Mojave (Morning|Afternoon|Evening)
Here is apple script to change wallpaper on macosx based on time of day (Morning\Afternoon\Evening) You could put desired pictures in folders:
Create folders
bash: mkdir -pv '$HOME/Pictures/Wallpapers/Morning', '$HOME/Pictures/Wallpapers/Afternoon', '$HOME/Pictures/Wallpapers/Evening'
Run script : "osascript ~/$HOME/Pictures/Wallpapers/wallpaper.scpt"
Create cron task in terminal: crontab -e Copy without quotes: "30 * * * * osascript $HOME/Pictures/Wallpapers/wallpaper.scpt" #Run script every 30 min.
Maybe better solution to use GUI Cron app: Cronnix