Apple OS X 10.10.3 Including New Photos App Is Available as Public Beta
Apple has started seeding the first public beta of OS X Yosemite 10.10.3 which includes the new Photos application.
Betas often provide an unstable experience hence it's not recommended to try them at the primary machine.
The Photos app is basically a replacement for iPhoto and aims to offer the same experience you'd get on mobile. The new tool from Apple makes it really easy to edit pictures and sync them across devices more seamlessly than before.
The new beta also include a tone of other new features. Among many other features are the new (diverse?) Emoji and two-factor login for Google accounts.
OS X 10.10.3 public beta is available for any registered beta user. For developers nothing is new, however, the release notes say that the public beta should improve the stability, compatibility and security of the Mac.