Hide wallpaper on Mac lock-screen

In keeping with the brilliant corporate strategy of the steady decline of Apple's UX since the passing of Jobs, Macs no longer let you separate your private desktop wallpaper from your lock-screen wallpaper.

Here's a quick hack to get past that.

create a small script to open your wallpapers randomly

cd ~/Pictures/Wps/
find . -maxdepth 1 -type f | sort -R | head -n 1 | xargs open

Then create a cron job to run the script periodically.

*/30 * * * * /Users/name/Desktop/wpcron.sh 

You may need to give cron permission to access your script and images.