In just a few months, there are thousands of apps that work with the Apple Watch. Soon there will be a whole lot more, as native apps come to watchOS 2.

That's just one of the big changes in store for Apple Watch users, as Apple went in detail about some of the new features coming to watchOS in the near future at its WWDC 2015 keynote.

Users can now customize their watch face with a photo or even a photo album, with the watch's face photo changing with every lift of the wrist. Another new watch face, called Time-Lapse, will show iconic locations from across the world shot over a 24-hour period.

A new "nightstand" mode will let you keep track of the time even while the watch is charging. The watch automatically goes into this mode when it is on its side and charging.

WatchOS 2 lets third-party apps display information on the watch face, and a new Time Travel function lets you turn the digital crown to look ahead on the day's events or go back to the past, up to 72 hours forward or backward from the present. All of the new features coming to Apple Pay will also work on watchOS 2.

One major new function is the ability to reply to emails directly from the watch, either with emoji, smart replies or by dictating the message. Siri on the Apple Watch can also be used to start and end workouts, or show Glances for various apps.

App developers will have more control than ever before as well with WatchKit. Developers will have the ability to use the watch's speakers, video capabilities, accelerometer, digital crown and more to make apps specifically designed for the Apple Watch.

The developer preview for watchOS launches today, with a free update to come for all users this fall.