Another such feature that has emanated from extensibility, which I very much welcome as an avid photographer, is the ability to use third-party photo editing tools directly from the Photos app. With this feature, you can add filters, instill text, and use other tools to edit all of your photos from a single app.
In Photos, select a picture you would like to edit, then tap on Edit. At the top left, you'll see a circle icon with three-dots in it: this is the new icon that appears when you have a third-party app on your device that connects with your built-in photo editor.
Note: The iPhone 6 and iPhone 6 Plus have the circle icon with three dots located at the bottom of the screen, since the device has more room for icons.
When you tap on the icon, you'll get a screen where a listing of your compatible apps will be. If you don't see any there, tap on More to view the apps that are compatible with the built-in photo editor, then enable them so they show up in the editing tools menu.
Now that the app is enabled, go back to the menu where you'll see the new app icon appear. Tap on it, and the tools that you would usually see only in the third-party app will now appear integrated in the Photos app.
With Litely, the filters from the app are available directly through the Photos app—just scroll down to select one, then swipe left and right to adjust its intensity.
Tap Done when you're finished and your photo will be saved with your edits. For all of you iPhoneographers, this is a feature that you're sure to love as it rolls out with more third-party apps.
Updated List of Compatible Third-Party Photo Apps
These are some of the current apps that are compatible in iOS 8's photo editor, available in the iOS App Store now: