Fixing “The dimensions of one or more screenshots are wrong” in App Store Connect

Three minutes of measuring usually settles this error. Read the real pixel size of each file, find the slot it is going into, and compare against the closed list below. Missing by a few pixels counts as missing.

Published: 5 September 2026 · Last reviewed: 1 November 2026

Measure before you guess

Start with the file, not with the slot. Design tools often display a frame in points or a rounded figure, so they are the wrong place to read a size from. On a Mac, ask the system:

sips -g pixelWidth -g pixelHeight shot.png

Write the two numbers down for every image in the failing set. Then look at which display class you were dropping them into. The error is raised for a whole class at once, and a single stray file is enough to trigger it.

The allow-list

Here is every accepted pair, grouped by slot. Portraits are given; for landscape, swap the two numbers.

The older slots work the same way: the 5.5″ slot takes 1242 × 2208 and the 4.7″ slot 750 × 1334. These values come from Apple's own screenshot specifications, read on 1 September 2026 and compared again on 12 October 2026. Nothing had moved, although Apple now names the classes by screen type instead of by diagonal. The full set for every device sits in the App Store screenshot sizes guide, and the screenshot size calculator will test a given file against it.

Why no tolerance exists

The wording of the message describes what you see, not what went wrong. Underneath, each slot owns a short list of pixel dimensions, and a file either equals one of them or it does not. There is no rounding, no closest match and no automatic crop.

That is why re-exporting « larger » or at « higher quality » never helps. A real example: 1290 × 2790 is refused and 1290 × 2796 goes through. Six pixels of height make the entire difference.

Right size, wrong room

By far the most frequent cause is a valid file in the wrong slot. Match each file to its row in the table above:

• 1290 × 2796 belongs in the 6.9″ slot. Put it in the 6.5″ slot, which takes 1284 × 2778 and 1242 × 2688, and it fails.
• A file only ever matches one row. If you fill several classes, export a separate set for each.
• iPhone and iPad keep separate lists, so an iPhone file does not carry over to an iPad slot.

Sizes that look plausible and are not

1080 × 1920 is a number everyone knows from video, and it appears on no iPhone list. 1290 × 2790 is just short of a real size, which is typical when a design tool rounds a frame. Scaling a smaller capture up to a listed size will satisfy the check but not the eye: the picture turns soft, and the store shows it at full size.

The size is right and it still fails: alpha

Apple's specification states that “Images can't include alpha channels or transparencies.” A Simulator capture made with xcrun simctl io <device> screenshot --type=png carries an alpha channel even if every pixel is opaque, on each device we tried. Flatten it, for example with sips -s format jpeg -s formatOptions 95 in.png --out out.jpg, then confirm with sips -g hasAlpha out.jpg.

Prevent it at the source

Render at the device's native size instead of resizing later. A screen of 393 × 852 pt at @3× comes out at 1179 × 2556 px through multiplication, so the file is correct the moment it is written. The arithmetic for each model is in iPhone screen sizes in points and pixels, and the wider rules are in App Store screenshot resolution.

If you will upload only one iPhone set, make it the one Apple has required since October 2026: the 6.3″ class (“iPhone with Dynamic Island (medium display)”), at 1206 × 2622 or 1179 × 2556. Apple scales it for the smaller classes, while the 6.9″ and 6.5″ slots can fall back only on each other.