As you might know, Apple with iOS 11 and macOS High Sierra introduced a new space-saving image file format, called High Efficiency Image File Format (HEIF).
If you own an iPhone 7 and newer or a 2017 iPad Pro, you may have noticed that updating to iOS 11 defaults the Camera app to capturing photos in Apple's new High Efficiency Image File Format (.HEIC files) and videos in the High Efficiency Video Coding (HEVC or H.265) format instead of the ubiquitous JPEG and H.264 media formats.
The popular Photoshop alternative, Pixelmator for iPhone and iPad, was updated on App Store this morning with support for iOS 11's drag and drop features on iPad and opening images saved in Apple's new HEIF file format.
Pixelmator for Mac was recently updated on Mac App Store with full macOS High Sierra compatibility, including the ability to open images saved in Apple's new efficient HEIF format and integrate with the stock Photos app as an external image editor.
The popular iOS camera app Camera+ was updated on App Store today with support for the new HEIF image format in iOS 11 and macOS High Sierra, portraiture photography on iPhone 7 Plus and iPhone 8 Plus, a more accurate viewfinder, a brand new Smile mode and more.
iOS 11 introduced support for modern HEIF and HEVC codecs developed by the Moving Picture Experts Group (not Apple's proprietary formats) that keep high-resolution photos and videos taken with iPhone and iPad from eating up all your available storage.