i'm not so sure about that, maybe i'm the only one, but i clearly remember when one of the iOS 10 versions release, the color/contrast/brightness on my lock screen wall paper was so badly changed, i tried many things to tweak the picture back to what it was but nothing help and when apple finally release the update to address the public outcry for the battery performance issue, my wallpaper magically looks normal to me again, and i don't think it's a coincident. Apple did that on purpose and push for new release phone sales.