But one problem is that HEIF and HEVC are not currently compatible with all applications, such as when a HEIF picture sent to Skype software friends, the other party will not receive, even if the other side is also used iOS 11 devices.
To this end, Apple in iOS 11 provides a solution, that users can be in the camera format will be “High Efficiency” to “Most Compatible” (most compatible). At this point, the picture is formatted in the normal JPEG / H.264 format.