Photos in macOS High Sierra adds a new always-on sidebar that presents albums and organization tools. A redesigned Edit view includes powerful new tools like Curves, for fine-tuning of color and contrast, and Selective Color, for making adjustments within a defined color range. Live Photos can now be edited with fun effects and Memories curates user photos and videos around several new topics. Photos now supports external editors, so Photoshop, Pixelmator and other apps can launch directly within Photos, with edits saved back to the Photos library. And for the first time, support for third-party project extensions gives users access to printing and publishing services, such as Animoto, ifolor, Shutterfly, WhiteWall and Wix, from right within the Photos app.