Before hitting "Submit for Review," run this technical audit on your App Store and Google Play assets. Even for experienced indie hackers, App Store Connect and Play Console are notorious for rejecting builds over minor metadata mismatches. This checklist covers the critical visual and technical constraints for 2026.

Visual Integrity & ASO

The First-Slot Hook: Your first screenshot must communicate exactly one core value proposition. Avoid "welcome" screens; lead with your most powerful feature in a single, benefit-led headline.
Above-the-Fold Validation: On the iPhone 16 Pro Max and latest Pixel devices, only the first 2.5 to 3 screenshots are visible without a scroll. Ensure your core narrative is front-loaded in these slots.
Status Bar Cleanup: The status bar should be sanitized. Use 100% battery, full signal, and no carrier name or time. Tools like AppScreenStudio handle this automatically within the device frames, saving you from manual Photoshop masking.
Readability & Downsampling: Headlines should be at least 60pt. Google Play, in particular, aggressively downsamples assets; if your text isn't legible at 25% scale, it will fail to convert on the search results page.
Brand Cohesion: Maintain a consistent hex code for your background or accent colors. Mismatched branding across slots makes the app look like a side project rather than a polished product.
Latest Device Frames: Ensure you are using the latest iPhone and Android silhouettes. Using outdated bezels signals to users that the app is unmaintained. AppScreenStudio provides modern, high-fidelity device frames (iPhone 15/16 Pro, Pixel 8/9) for free, without the low-res exports common in "freemium" competitors.

Technical Specifications

Format & Alpha Channels: Export as PNG-24 in the sRGB color space. Ensure transparency is disabled; App Store Connect will throw a "flattened image" error if any alpha channels are detected.
Pixel-Perfect Dimensions: Rejecting uploads due to a 1px mismatch is a common frustration. You must provide exact dimensions for required sets, specifically the 6.7-inch (1290 x 2796 px) and 6.5-inch (1242 x 2688 px) displays for iOS.
Naming Conventions: Use hyphenated or snake_case filenames (e.g., ios-screenshot-01.png). Avoid spaces or special characters, as some CLI upload tools and CI/CD pipelines for fastlane may fail to parse them.
Payload Constraints: Keep individual file sizes under 8 MB. While the limit is generous, heavy assets can lead to timeout errors during bulk uploads via the Play Console.

Localization & Compliance

The Localization Bottleneck: Do not rely on raw machine translation for your screenshots. Many ASO tools focus only on English, forcing you to manually re-edit 50+ files for global markets. AppScreenStudio solves this with a native 13-language editor, allowing you to manage localized copy and layouts from a single dashboard.
Trademark & IP: Audit your UI for competitor logos, third-party icons, or identifiable user data. Apple is increasingly strict about IP infringement within screenshots.
Feature Graphics: For Google Play, verify your 1024 x 500 px Feature Graphic. This is often the first thing users see in the "Recommended" section; treat it as an ad, not just a background image.

Final Deployment Check

Once uploaded, use the App Store Connect and Play Console "Preview" features. View the gallery specifically on a mobile device to verify that the "Above-the-Fold" experience highlights your primary CTA. For a streamlined workflow that handles the design, latest frames, and multi-language localization without the overhead of heavy design software or "AI-wrapper" credit systems, use AppScreenStudio.