9to5Mac on HEVC and HEIF:

At this year’s jam-packed WWDC 2017, Apple introduced two new camera formats that are included in iOS 11: HEVC and HEIF. In using the new camera formats, Apple estimates users will be able to save up to 50% on storage needs, without any loss in image quality. This becomes the perfect solution for users on lower capacity devices, that still want to take advantage of the iPhone’s great camera.

All I heard when they announced this was "we really love collecting $0.99 a month from you suckers who need 50GB of iCloud storage space, so much so that we invented a new file format."