How to Make an iOS App Icon: 1024×1024, Square, No Alpha Channel

Apple's rules for the App Store icon are short, and none of them are visible by looking at the artwork. A logo can look perfect in your design tool and still be rejected when you upload the build. Here are the rules, the one that catches most people, and how we turned our own logo into an icon that passes.

What Apple checks

• 1024 × 1024 pixels, exactly. Since Xcode 14 that single image is all you need. iOS makes the home screen, Settings, Spotlight and notification sizes from it.
• Square, with square corners. Don't round the corners yourself. iOS applies its own rounded mask, and pre-rounded corners end up with odd slivers of background around them.
• PNG.
• No transparency, and no alpha channel. This is the one that trips people up.

The alpha channel trap

A PNG can store a fourth value per pixel, called alpha, that says how opaque it is. App Store Connect rejects an icon that has transparent pixels, and it also rejects one that merely has an alpha channel, even if every pixel in it is fully opaque. The upload error (ITMS-90717) says it outright: the icon "can't be transparent nor contain an alpha channel."

Filling the background with a solid color fixes the first problem but not the second. Most design tools, and anything that exports through a web browser's canvas, save PNGs with an alpha channel by default, so an icon with a solid white background can still be refused.

On a Mac, you can check a file before you upload it:

sips -g hasAlpha AppIcon.png

You want to see hasAlpha: no. If it says yes, the icon needs re-exporting without alpha. In Preview, choose File → Export, pick PNG and untick Alpha.

Turning a wide logo into an icon

Our logo is a typical starting point: 1200 × 693 pixels, wide rather than square, with a transparent background and a wordmark under the symbol. We made the icon with the Image Crop Tool:

1. Upload the logo. The Apple App Icon (1024×1024) preset is selected by default.
2. Pick a background color. We used a pale blue, #eaf1ff. It fills everything that was transparent.
3. Drag the corners of the square selection to frame the part you want, and drag inside it to move it. The image is cropped, never stretched.
4. Click Crop Image and download the PNG.

We checked the downloaded file: 1024 × 1024, three color channels, no alpha. The tool writes icons without an alpha channel, so it passes the check above.

Leave the wordmark out

Our first attempt kept the whole logo in the frame. At 1024 pixels it looked fine. At home-screen size the word "CloudToolbox" shrank to a smudge, and the symbol above it got small too. Cropping to the symbol alone made it about twice as big and much easier to recognize. The app's name is printed under the icon anyway.

Checklist before you upload

• Exactly 1024 × 1024 pixels.
• PNG, with sips -g hasAlpha reporting no.
• A solid background all the way to the edges, with square corners.
• The logo isn't stretched or squashed.
• It still reads when you shrink it to the size of a fingertip.