4. Remove red-eye
Red-eye (caused by reflected camera flash) is a common problem in portraits. Photos has a built-in red-eye removal tool, which will appear if the app detects a face in shot.
Tap the tool (the eye-shaped icon), then tap on each affected eye. Sometimes you need to tap a few times for Photos to locate the red-eye; it can help if you pinch to zoom in first. Tap Done to finish.
The new adjustment options offer both simple and advanced modes. Tap the dial icon, then tap the option you want to adjust (Light, Color or B&W). You'll see a spectrum of small preview images.
Drag this to apply the adjustment (lightening or darkening the image, increasing or reducing colour saturation, and so on). Tap Done to apply or Cancel to reject it.
6. Expert editing
Want more control? Either tap the menu icon that shows three horizontal lines or swipe the preview slider to reveal further controls (such as Saturation, Contrast and Cast).
You can use these sliders to adjust each specific setting and fine-tune images with precision. Either swipe back to the basic slider, or tap the threeline icon and hit the main icon to return.
7. Install and activate extensions
Extensions are a new addition to the Photos app, and they change everything. First you need to install a photo editing app that supports extensions, such as Pixelmator, ProCam and Camera+.
After installing the app you'd like to use, open Photos, pick a shot and tap Edit. Now tap the Extensions icon (the circle with three dots), tap More and then activate the extension for the relevant app.
8. Access Extensions
Your chosen app now appears in the list that pops up when you tap Extensions in Photos. Tap it (you might have to OK an alert the first time) and you will see a bunch of new editing options, depending on the extension app that you have chosen.
Pixelmator, for example, offers a range of 14 different effects, while Camera+ contains a whole suite of more traditional photo editing options.
9. Add effects
Here we're adding some cool graphical effects using and app called Fragment. When finished, tap Done to return to Photos, then Done again to save all your changes.
Reselect the image and tap Edit, then tap and hold one finger on the image to view the original. This enables you to compare it with your edited version. To remove all edits, tap Revert, then Revert to Original. You can do this at any time.