If you have a bunch of images you don't want to wait to load them until in view especially on a slow connection. If you lazy load the images then that means every time the user scrolls they have to wait for an image. No one is going to wait for your image to load, so they will scroll on. You then cause a bottleneck in your javascript because the user is scrolling and you are using JS to download images which is not optimal.
The experience you want is to load the first image and then load then next image before the user gets to it so that it is ready when the user scrolls. Our browsers do a great job of this already. Don't reinvent the wheel. Our browsers have been optimized to download images the right way. And if you want to save bandwidth then use responsive images and let the browser determine the best size to download.
I've implemented lazy load on mobile and learned this first hand. I thought I needed lazy load, but to my surprise, the browser actually knows how to load images the right way. My app actually had less jank and loaded images faster when I left the images up to the browser.
Stop over engineering image loading please :-)