sudo permissions

[rubenvarela]

Instead of running with sudo, an option is to test if you can write to the destination file. If you can't, you could execute

sudo chown $(whoami):$(groups | cut -d' ' -f1) /Library/Caches/com.apple.desktop.admin.png

This will change the ownership of com.apple.desktop.admin.png thus allowing the user to change the image without sudo.

[rubenvarela]

I don't know if theres's a shorter way of getting the group.

You can assume staff, but I don't know if that can change, or under what circumstances it does.

[chrisetheridge]

To be honest, I think the best would to just keep with sudo permissions. Or what do you think? I will gladly look at a PR implementing this :)