What the Checker Looks At
- Exact pixel dimensions. App Store Connect only accepts specific sizes for each device slot. The checker matches your file against every accepted size, in portrait and landscape, and names the slot it fits.
- Alpha channel. PNGs with an alpha channel are rejected even when the image looks fully opaque. The checker reads the PNG header to find out.
- File format. Both stores take PNG and JPEG. WebP, HEIC and other formats are flagged.
- Google Play rules. Each side between 320 and 3840 px and the long side at most twice the short side, plus a warning for files over the 8 MB upload limit.
When a size does not match, the checker shows the closest accepted size and tells you whether your image has the same shape (a simple re-export) or a different one (it needs a crop or a new layout).
Sizes the App Store Accepts
These are the sizes most apps need. The full App Store screenshot size guide lists every slot, including older phones, desktop, TV and watch.
| Slot | Accepted Sizes (Portrait) | Needed? |
|---|---|---|
| Phone, medium display (6.3" / 6.1" class) | 1206 × 2622 px 1179 × 2556 px | Required |
| Phone, large display (6.9" / 6.7" class) | 1320 × 2868 px 1290 × 2796 px 1260 × 2736 px | Recommended as your master size |
| Phone, large display with notch (6.5" class) | 1284 × 2778 px 1242 × 2688 px | Only if the large slot above is empty |
| Tablet, 13" display | 2064 × 2752 px 2048 × 2732 px | Required for tablet apps |
| Foldable phone (outer / inner display) | 1398 × 2034 px 2007 × 2853 px | Required from April 2027 |
Google Play Rules
| Asset | Rule |
|---|---|
| Phone screenshots | 320 to 3840 px per side, long side at most 2× the short side. JPEG or 24-bit PNG without alpha. |
| Recommended for featuring | 9:16 portrait at 1080 × 1920 px or larger, or 16:9 landscape at 1920 × 1080 px or larger. |
| Feature graphic | Exactly 1024 × 500 px. JPEG or 24-bit PNG without alpha. |
See the Google Play screenshot size guide for tablets, large screens and wearables.
How to Fix a Failed Check
- Wrong size, same shape. Re-export from your design tool at the exact size shown. Do not upscale a small file, because text and edges will blur.
- Wrong size, different shape. The layout needs to change. Stretching a phone screenshot to a tablet canvas distorts the device frame and text.
- Alpha channel. Export a 24-bit PNG (sometimes labelled "PNG-24 without transparency") or a JPEG. Placing the image on a solid background before exporting also works.
ReinShots Studio avoids all three: it exports each store size natively from one design and writes PNGs without an alpha channel.
Frequently Asked Questions
Are my screenshots uploaded anywhere?
No. The checker reads each file with your browser's File API and inspects it on your device. Nothing is sent to a server, so it is safe to use with unreleased app screenshots.
How does it detect an alpha channel?
It reads the PNG header. A PNG with colour type 4 or 6, or with a tRNS chunk, carries transparency information even when every pixel looks opaque, and App Store Connect rejects those files.
My size is not accepted. How do I fix it?
If the checker says the closest size has the same shape, re-export your design at that exact size. If the shape differs, stretching will distort the image, so crop it or lay the screenshot out again on the correct canvas.
Sources
- Screenshot specifications, App Store Connect Help. Read on 10 November 2026.
- Add preview assets to showcase your app, Play Console Help. Read on 10 November 2026.
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