What the App Icon Checker examines
The checker reads the real decoded pixels rather than trusting the file extension or MIME type. It reports the checks below and explains anything that needs attention.
| Check | What it reports |
|---|---|
| Dimensions | Actual width × height in pixels. |
| Square status | Whether the image has a 1:1 aspect ratio, which app icons require. |
| Aspect ratio | The reduced ratio, for example 1:1 or 4:3. |
| Format | PNG, JPEG or WebP, with a reminder that store icons are expected to be PNG. |
| File size | The exact byte size, with a warning above 10 MB. |
| Transparency | Whether sampled pixels contain an alpha channel below fully opaque. |
| Readability | Whether the browser could decode the file as a valid image. |
What this tool cannot verify
A browser cannot reproduce a store review. The checker does not inspect colour profiles, embedded metadata, copyright, brand rules or the appearance of the icon after each platform applies its mask. It also cannot guarantee acceptance by Apple or Google.
Treat a passing result as “meets the technical checks performed by this tool”, not as official approval. Always review the current platform requirements before submitting.
Common app-icon problems
Not square
A 1024 × 1000 export looks almost square but still fails a 1:1 requirement. Re-export at exact square dimensions or use the App Icon Resizer to crop and generate the correct sizes.
Transparency in the master icon
Rounded corners or a transparent background can look fine in a design tool but fail an opaque-icon requirement. Flatten the artwork onto a solid background and export again.
JPEG instead of PNG
JPEG compression creates artefacts around sharp edges and does not preserve transparency. Use PNG for icons and keep JPEG for photographic store graphics.
Too little detail at small sizes
An icon can pass every technical check and still be unreadable at 20 or 40 px. Preview the small outputs before submitting.
Frequently asked questions
What does the App Icon Checker check?
It checks dimensions, square status, aspect ratio, detected format, file size, transparency sampled from decoded pixels, and whether the image can be read. It does not perform an official store review.
Does a passing result guarantee App Store approval?
No. Passing means the image meets the technical checks this browser can perform. Apple and Google apply additional content, branding and metadata rules that no local checker can verify.
How is transparency detected?
The decoded image is sampled on a small canvas and the alpha channel is inspected. Fully or partially transparent regions are reported. Colour profiles and other metadata are not examined.
Is my icon uploaded for analysis?
No. The file is decoded and analysed in your browser. Nothing is uploaded, logged or stored, and the analysis is discarded when you reset or close the page.
Which formats can I inspect?
PNG, JPEG and WebP files that your browser can decode. Unsupported or corrupted files produce a clear error instead of a misleading result.