What I have noticed is that when you use a launcher that goes beyond two screens wide is that the wallpaper still is only one and half screens wide and does not allow for an increase in the virtual space to accommodate the wider wallpaper dimensions. At the moment when you choose a panoramic picture it only allows you to use a small percentage of the picture while cutting off the sides. Go on add more screens to current android launcher. The wallpaper has no ability to adjust for the extra width you just added. In fact if you add quite a few extra screen you will notice the scrolling from side to side will have less movement.

What if your phone's screens were thought of like computer screens...
The more screens that you add to your android launcher would be an increase in virtual space just like multiple monitors. So you could use say panoramic pictures to full take advantage of a phone with 5, 6, 9, 15, even 45 screens. So when I scroll side to side it actually moves along with the wallpaper.

This app will allow you to customize how wide your wallpaper versus how many screens you have on your phone for the ultimate setup.

One of the request we have gotten was for transitional effects. Well to be honest most launchers have those built in and we would therefore be creating another launcher to add this in. Also it is dependent upon your launcher if you are using a continuous photo / image and would like for it to wrap around when you scroll to the end to create a seamless wallpaper.

Instructions

Download the application Ultra Wide HD Live Wallpaper or Ultra Wide HD Live Wallpaper Lite and install.
Go to your live wallpaper. Select HDLWP. Go to settings, customize your settings and then apply.
For more info

Description of the settings | Screenshots | Where to find wider images

Adocus & ScheffsBlend