This is the same wallpaper that you have seen back when the Samsung Galaxy S5 made its debut at the MWC 2014. While there are a lot of knockoffs out there, not all are high quality. We have managed to grab the official one as we were present there at the MWC.
It is of high resolution 2160×1920 and would work fine on just any phone that lets you set a custom wallpaper. We are using it on our Galaxy S4 and it looks great. Many have even mistaken it for an S5 since they have seen it at the official launch event.
The official wallpaper looks kind of 3D as both S4 and S5 quite glossy coating on their displays. We will be updating this thread once we get hold of other official wallpapers.