Chrome Web Store requires at least one screenshot before an extension can go live; the store upload form blocks submission without one. Screenshots at the specified 1280x800 or 640x400 dimensions are how the majority of users decide whether to install — a missing screenshot means a blank listing that converts at near-zero. Store search results show the primary screenshot thumbnail as the visual hook; without it, your listing is invisible compared to competitors. The chrome-cws-screenshots policy treats this as a hard submission requirement.
High because zero screenshots block Chrome Web Store submission entirely and eliminate the primary visual conversion surface for potential installs.
Capture your extension's main UI or popup at exactly 1280x800 pixels (preferred) or 640x400 pixels, save as PNG, and place it in a screenshots/ directory.
screenshots/
screenshot-1.png (1280x800)
screenshot-2.png (1280x800)
Show the extension in use — opened popup, options page, or injected UI on a real page. Avoid screenshots of a blank or loading state. On macOS, use Cmd+Shift+4 with a locked selection to capture at exact pixel dimensions, or use a browser devtools device emulation set to 1280x800.
ID: extension-store-readiness.screenshot-docs.primary-screenshot
Severity: high
What to look for: Check for a screenshots/ directory or similar asset directory. Look for at least one screenshot file with dimensions 1280x800 pixels (preferred for store listing display) or 640x400 pixels. Verify the file is a valid PNG or JPG image.
Pass criteria: At least 1 screenshot exists with dimensions 1280x800 or 640x400 pixels. The image is a valid PNG or JPG. Count the total number of screenshots found.
Fail criteria: 0 screenshot directories found, 0 screenshots present, or screenshot dimensions don't match 1280x800 or 640x400.
Skip (N/A) when: Never — at least one screenshot is required for Chrome Web Store.
Detail on fail: "No screenshots directory found" or "Screenshot dimensions are 800x600 (should be 1280x800 or 640x400)".
Remediation: Create a screenshot showing your extension's main UI or functionality:
1. Open your extension's popup/options page
2. Take a screenshot at 1280x800 resolution (or 640x400)
3. Save as screenshots/screenshot-1.png
4. Add to your project's public assets
A good screenshot shows the extension in action, highlighting key features.