In iOS 11, the photos and videos you take will no longer be encoded in the compatible formats you’re used to. Instead of JPG for images and MPEG-4 for video, they’ll use High Efficiency Image Format (HEIF) and High Efficiency Video Format (HEVC), respectively. Files in these newer formats are about half the size of JPG and MP4 files of similar quality.
Encoding files in HEIF (using the .HEIC extension) and HEVC (using the .MOV extension) requires a bit more processing power, so this change is only coming to the iPhone 7, iPhone 7 Plus, iPhone 8, iPhone 8 Plus, iPhone X, and the latest generation iPad Pro models. Also, it’s worth noting that this change will only affect new photos you capture, iOS11 won’t change any photos or videos you’ve already taken.
While HEIF and HEVC are great in theory, they aren’t as widely supported as JPG and MP4 yet (which are essentially universal at this point). For example, you need to upgrade your Mac to macOS High Sierra for it to be able to edit HEIF and HEVC files. And if you use Windows 10, they aren’t compatible out of the box yet.
If you’d rather capture your photos and videos in a more widely compatible format, you can do so with a simple settings toggle. Here’s how.
Go to Settings > Camera > Format and select Most Compatible instead of High Efficiency.
Now your iPhone will keep using the older, larger, more compatible formats.