Mac loses the ability to set desktop image after a few days of automatic setting

Question

I have a script that pulls images from Reddit and sets them as my wallpaper. This works fine for the first few days, though after that it just stops changing the wallpaper. The images continue to download to the local folder but for some reason I just can't set my wallpaper anymore. Even doing right click 'set desktop picture' on an image or manually using my automator app.

The only way to fix this is to reset it by going to wallpaper in settings and manually setting it. I've even tried using different methods of setting the wallpaper but the result is the same.

Does anyone know what might be causing this or how to debug?

Answer 1

Eventually figured out that "there is a problem where OS X would cache the wallpaper in RAM and not check to see if the picture file had changed given that it was using the same filename each time." So solved by just using the hash of the image as a filename.