The Android N Dev Preview 3 is jam-packed with new features, but you’ll likely not be able to play with any of them unless you install the developer preview on your Nexus device. The process is fairly simple, but it only works if you own a Nexus. That being said, you can give your non-Nexus device a splash of Android N with the four new wallpapers which were included in the latest preview.
All four full resolution (2880×2560) wallpapers from Android N can be downloaded in a single zip file. To download them individually from your Android device, long pressing on the image thumbnail and tap “Save link.” The wallpaper will then show up in your Downloads folder.