The iPhone 5 has a longer screen than its predecessors the iPhone 4 and iPhone 3GS (actually, it’s the first time the iPhone screen size has been changed since the original iPhone was launched).
You can use pretty much any image you want as the wallpaper and the operating system will do a good job of automatically sizing and cropping, but if you want more control over it, there are two options.
Cropping and Resizing on the Phone
If you’re using a photo taken with the iPhone’s camera, using the photo as your wallpaper is simple enough. There are two main ways:
1. Go to Camera > Camera Roll, choose the image you want to use, hit the Send To icon, and then choose Use as Wallpaper.
2. Alternatively, go to Settings > Brightness & Wallpaper, and then click on one of the two live screenshots. You can then choose any image from your Camera Roll (where the photos taken with the phone go).
When you click on an image thumbnail in Camera Roll, you’ll then get the option to Move and Scale the image to your liking. Zoom in and out with the usual pinch gestures and drag to move.
When you hit the Set button, you’ll be given the option to set the Lock Screen, the Home Screen, or both. That means, of course, that you can set different images for each.
Cropping and Resizing in Lightroom or Aperture
If you’d prefer to have finer control, you can of course do your image manipulation elsewhere in Lightroom, Aperture, Photoshop, Gimp, or whatever other image editing software you use.
The ideal dimensions to use for the crop are 1136 pixels tall by 640 pixels wide.
The ppi (pixels per inch) or dpi (dots per inch) setting doesn’t make any difference, but if you’re going to set it, you might as well set it to the iPhone’s screen display of 326ppi.
1. Create a virtual copy of the image you’ll be using. This isn’t essential, but it makes things easier.
2. In the Develop Module, hit the Crop tool. To the right of Aspect, click on the drop down menu (if the lock to its right is locked, unlock it by clicking on it).
3. Click on Enter Custom…
4. Enter 11.36 and 6.4, then OK.
5. Move the image so focus on the part of the image you want to feature and then double-click on the image to save the crop.
6. Go File > Export. Make sure Export To is set to Hard Drive, then set your output folder, filename, etc, however you want.
7. Under File Settings, choose JPEG for Image Format and sRGB for Color Space. Choose whatever quality setting you like. Since filesize isn’t a core consideration here, I use about 90.
8. Under Image Sizing, choose Width & Height to these:
9. If you’d like Output Sharpening, choose it here. I like to set for Screen and Standard.
There are a few different ways to get the image onto your phone, but I often find the easiest is just to email it to myself, then open the email on the phone, tap and hold on the displayed image, and Save Image. It then ends up in your Camera Roll and you can proceed as above. You can also use Dropbox or connect your phone to iTunes on your computer.