Tap on the photo you posted and click on Save image. Then go to Photos, choose that photo and click on the forward symbol ( the rectangle with the arrow sticking on top). Then scroll through the choices until you seeSave as Wallpaper. Click on that. Now center it by sliding the image until it is where you want and then save it to how you want to use it.
I've moved your new post/thread to this one, where you already asked the same favor. Please don't start duplicate threads or post the same topic twice. It's making it hard to follow, and duplicate threads or posts are also against our rules.
Please keep any discussion of this kind to this thread only.