How to Remove the Alpha Channel from Screenshots and App Icons

Quick answer: An alpha channel is the transparency layer in a PNG (RGBA instead of RGB). App Store screenshots and the iOS App Store icon can't include one, and Google Play screenshots and feature graphics must be JPEG or 24-bit PNG. Check a file with sips -g hasAlpha shot.png, then remove alpha by exporting from Preview with Alpha unchecked, converting to JPEG, or running ImageMagick with -alpha remove -alpha off.

The pattern: anything shown as a rectangle on a store page must be opaque. The only places transparency is expected are the iOS dark icon variant and launcher icon layers, which the system composites itself. Store-specific icon rules are in iOS app icon requirements and Google Play icon requirements.

• App Store Connect, screenshots: an upload error stating that images can't contain alpha channels or transparencies. It mirrors the rule in Apple's screenshot specifications.
• Xcode or App Store Connect, app icon: an "Invalid App Store Icon" error (ITMS-90717), which typically says the App Store icon can't be transparent or contain an alpha channel.
• Play Console: the screenshot or feature graphic upload is refused because it isn't a JPEG or 24-bit PNG. The wording varies, so if the size is valid and the upload still fails, check for alpha first. If App Store Connect complains about size instead, see fixing wrong screenshot dimensions.

The trap: a PNG can look completely opaque and still fail. Many tools save every PNG as RGBA, even when no pixel is transparent. Validators look at whether the file has an alpha channel, not at what you see, so "but there's no transparency in it" doesn't help.

On a Mac, sips is built in:

• sips -g hasAlpha shot.png prints hasAlpha: yes or hasAlpha: no.
• sips -g hasAlpha *.png checks every PNG in a folder at once.

On macOS or Linux, file shot.png prints a line such as "PNG image data, 1290 x 2796, 8-bit/color RGBA". RGBA means an alpha channel; RGB means none. A PNG described as 8-bit/color RGB is what Google calls a 24-bit PNG (8 bits for each of three channels); RGBA adds a fourth channel, making it 32-bit.

Prefer not to use the terminal? Drop your files into the free screenshot size checker. It reads them in your browser, flags any PNG with an alpha channel, and shows which App Store or Google Play slot each image fits.

With Preview (one file at a time)

1. Open the image in Preview.
2. Choose File > Export.
3. Set Format to PNG and uncheck Alpha. Or choose JPEG and set quality to the highest setting.
4. Save under a new name and check it with sips -g hasAlpha.

With sips (no extra installs)

sips can't drop the alpha channel directly, but converting to JPEG removes it, because JPEG has no transparency:

• sips -s format jpeg -s formatOptions 100 shot.png --out shot.jpg creates a full-quality JPEG.
• If you need PNG, convert back: sips -s format png shot.jpg --out shot-flat.png. The result reports hasAlpha: no.

Transparent areas are filled during conversion, often with white. If your design has deliberate transparent regions, add a solid background in your design tool first, so you control the color.

JPEG is accepted by both stores, so you can usually stop after the first command. A full-quality JPEG of a screenshot is often smaller than the PNG, which also helps with Google Play's file size limit.

ImageMagick isn't on macOS by default, but it's the standard tool for batches on Mac, Linux and Windows once installed:

• magick shot.png -background white -alpha remove -alpha off shot-flat.png composites the image onto white and removes the channel.
• magick mogrify -background white -alpha remove -alpha off *.png does the same for every PNG in the folder, overwriting the originals. Copy the folder first.
• On ImageMagick 6, use convert instead of magick.

With Python and the Pillow library, python3 -c "from PIL import Image; Image.open('in.png').convert('RGB').save('out.png')" drops the channel. It doesn't composite onto a background, so fully transparent pixels may turn black; use ImageMagick if your image has transparent areas.

Fixing exports at the source saves you from running these commands before every release:

• Figma: frames with no fill export with transparent areas. Give every screenshot frame a solid or gradient background, and export store screenshots as JPG, or verify the PNG with sips before uploading. See Figma App Store screenshots.
• Canva: when you download a PNG, leave the transparent background option off, or download a JPG.
• Simulator captures: use File > Save Screen in the Simulator instead of a macOS window capture, which adds a transparent shadow around the window. Xcode Simulator screenshots covers the options.
• App icons: flatten the 1024 px icon onto its background before adding it to the asset catalog. ScreenShipper's free icon generator exports the AppIcon set without an alpha channel.

Alpha problems come back every time someone exports from a new tool. Add one line to your pre-upload routine: run sips -g hasAlpha on the export folder, or drop it into the checker, and fix anything that says yes. It takes seconds and avoids a failed upload on release day. The App Store screenshot checklist includes this and the other pre-upload checks.