Generate store screenshots in every size (agent prompts)
Generating store screenshots in every required size is the most tedious part of
a release. These copy-paste prompts hand the work to an AI coding agent (Claude
Code, etc.): capture from a simulator/emulator, resize to each store’s exact spec,
strip the alpha channel, and file them under assets/.
Required sizes
Section titled “Required sizes”Stores reject the wrong dimensions or any alpha channel, so target these exactly:
| Asset | File name | Size (px) | Notes |
|---|---|---|---|
| iPhone 6.9” | iphone-0N.png | 1320 × 2868 | App Store iPhone |
| iPad 13” | ipad-0N.png | 2064 × 2752 | App Store iPad |
| Android phone | phone-0N.png | 1344 × 2688 | Play; long side ≤ 2× short side |
| Android tablet | tablet-0N.png | 2048 × 2732 (or 16:10) | Play tablet (optional) |
| App icon | app-icon.png | 1024 × 1024 (App Store) · 512 × 512 (Play) | no alpha |
| Feature graphic | feature-graphic.png | 1024 × 500 | Play only |
Drop the results into assets/new/ (the New variant) — or assets/template/
to bundle a demo set. See The integrated site for the folders.
Prompt 1 — capture from the iOS Simulator
Section titled “Prompt 1 — capture from the iOS Simulator”You are working in a Capacitor/iOS app. Capture App Store screenshots from theiOS Simulator for these device sizes and save raw PNGs to ./shots-raw/ios/:
- iPhone 6.9" (e.g. "iPhone 16 Pro Max") → iphone-01..05.png- iPad 13" (e.g. "iPad Pro 13-inch (M4)") → ipad-01..05.png
Steps for each device:1. boot the simulator: `xcrun simctl boot "<device>"`2. launch the app and navigate to each of the 5 key screens (Discover hub, go2048, Zip, Patch, Sudoku)3. capture: `xcrun simctl io booted screenshot ./shots-raw/ios/<name>-0N.png`
Report the exact pixel size of each captured file when done.Prompt 2 — capture from the Android emulator
Section titled “Prompt 2 — capture from the Android emulator”Capture Google Play phone screenshots from a running Android emulator and saveraw PNGs to ./shots-raw/android/ as phone-01..05.png:
1. confirm a device: `adb devices`2. open the app, navigate to each of the 5 key screens3. capture: `adb exec-out screencap -p > ./shots-raw/android/phone-0N.png`
Report each file's pixel size. Do not resize yet.Prompt 3 — process to exact store specs (resize + strip alpha)
Section titled “Prompt 3 — process to exact store specs (resize + strip alpha)”Process every raw PNG in ./shots-raw/ into store-ready assets in ./assets/new/.Stores reject alpha channels and wrong dimensions, so:
- iPhone → resize/letterbox to exactly 1320x2868, strip alpha- iPad → 2064x2752, strip alpha- Android phone → crop/resize to 1344x2688 (long side must be ≤ 2× short side), strip alpha
Use ffmpeg, scaling to fit then padding (no distortion), forcing RGB (no alpha):
ffmpeg -y -i in.png \ -vf "scale=1320:2868:force_original_aspect_ratio=decrease,\pad=1320:2868:(ow-iw)/2:(oh-ih)/2:white,format=rgb24" \ -pix_fmt rgb24 assets/new/iphone-01.png
Keep names iphone-0N.png / ipad-0N.png / phone-0N.png. After processing, verifyeach output is the exact target size and has NO alpha channel (e.g.`ffprobe -show_streams` → pix_fmt rgb24). Report a table of file → size → alpha.Prompt 4 — app icon & Play feature graphic
Section titled “Prompt 4 — app icon & Play feature graphic”From the master app icon (./icon-master.png, square, ≥1024px), produce:
- assets/app-icon.png 1024x1024, NO alpha (flatten onto white)- a 512x512 copy for Google Play- assets/feature-graphic.png 1024x500 (place the icon + app name on a solid brand-color background; no alpha)
Use ffmpeg/ImageMagick, force rgb24 (no transparency). Verify final sizes andthat none has an alpha channel.Prompt 5 — one-shot, end to end
Section titled “Prompt 5 — one-shot, end to end”Produce a complete, store-ready screenshot set for <APP NAME> and place it in./assets/new/:
1. Capture 5 screens each from the iOS Simulator (iPhone 6.9" + iPad 13") and the Android emulator (phone).2. Resize/letterbox to the exact store specs and STRIP ALPHA: iPhone 1320x2868 · iPad 2064x2752 · Android phone 1344x2688.3. Generate app-icon.png (1024x1024, no alpha) and feature-graphic.png (1024x500).4. Name files iphone-0N.png / ipad-0N.png / phone-0N.png and put them in assets/new/ (icon + feature graphic in assets/).5. Print a final table: file → dimensions → has-alpha (must all be "no").
Then I will open the Playground, switch to the New variant, and Review Diff.Verify the result
Section titled “Verify the result”Open the Playground, make sure you’re on the New variant — your screenshots replace the placeholders. Run Review Diff against Current and the first-release checklist to confirm every required size is present before you submit.