Prevent wallpaper to slide when sliding the home screen
That's the way every android homescreen work. Wallpaper scrolls along with the screen. Stock homescreen doesn't allow us to customize this. You need to get a replacement for homescreen. Like Apex launcher, Smart launcher 2, Solo or Nova launcher etc. They allow you to disable wallpaper scrolling. (or) There's an app called Wallpaper Wizardrii in Play Store to set the wallpaper in the way you want. Give it a shot.