SAN FRANCISCO—Google unveiled its new mobile operating system, Android M at its I/O developer conference Thursday, along with a new photo app already garnering praise and updates to Android Wear.

Android M resembles the previous version, Lollipop, but optimizes powr use adds new services and alters how apps interact.

Android M changes the app update process to make it less clunky. Previously, Android required asked for a batch of permissions. Now there are fewer update categories. You can also check everything a given app accesses.Instead of asking for permissions when a app is installed, it requests them when it is activated, so users can see the requests in contex.

Chrome custom tabs is supposed to make loading pages faster. It preloads elements such as passwords and autofill.

The new feature Doze uses motion detection to go into deep sleep when its inactive for longer periods. An Android M device will still use alarms and respond to high-priority messages. Android M also supports USB Type-C.

Now on Tap, a new program on Android M will bring up cards with information relevant to whatever you’re doing when you hold down the home button. In email, it would bring up information about whatever is mentioned, a movie, event, etc. If you’re messaging about dinner, it will give you restaurant listings with buttons for Yelp, maps, and Open Table.

Google Photos updates the photo app on Android phones. It will now back up an unlimited number of photos or videos free, organize them on a timeline, and group them by locations using advanced auto-tagging.New tools aid sharing photos, making collages or movies from them.

Google also added new apps to its smartwatch OS. Those include an easy way to call for an Uber ride, a new app launcher, and other updates.

Android Pay revamps Google Wallet, converting to a peer-to-peer service. It lets users buy at NFC terminals and make purchases with a single tap within apps. It also incorporates loyalty offers, a feature gleaned from its recent acquistiion of Softcard. Google says it has about 700,000 merchant partners.

Google has made it easier for app developers to get content indexed by its search engine, offering what it calls deep-links that go to specific places in an apps. This feature, already available for Android apps is expanding to the iOS.

Also for developers, Google offers improved tools for tracking if an app user is coming from paid ads or an organic installation. It is providing better ad targeting so developers can promote in-app buys only toward customers who have a habit of making those purchases. A new app promotion tool gives developers a centralized spot to run, measure and serve ads.