Lock screen wallpaper location

The Samsung Galaxy S4 comes with a TripAdvisor lock screen wallpaper that rotates images every X hours of places around the world. Every now and then, it has really cool ones that I would potentially like to save to use as my lock screen permanently, but I can't figure out where in the filesystem they are stored. I have found a couple of posts saying it is located in /data/data/com.android.settings/ or something like that, but my /data folder is empty. TL;DR: Where does Android save the current lock screen image?