Images can now make use of the wide color gamut found on recent Macs, iPhones, and iPads, Apple said in iTunes release notes. The company has also made it possible to import images and videos from Photos via the Media Browser or drag-and-drop.
The software also includes unspecified “performance and stability improvements.” iBooks Author is a free download, and runs on Macs with OS X 10.11 or better.
The release coincides with the launch of macOS High Sierra, though it doesn’t explicitly take advantage of new technology. High Sierra mainly adds support for standards like HEVC video, HEIF images, Metal 2 graphics rendering, and the Apple File System that originally debuted on iOS. It also includes improvements to apps like Safari and Photos, which might have warranted the iBooks Author changes.