chromium/chrome/test/data/extensions/api_test/extension_resource_request_policy/web_accessible/accessible_resource_with_csp.html

<meta http-equiv="Content-Security-Policy" content="img-src 'none';">
<img onload="document.title='Loaded'" onerror="document.title='Image failed to load'" src="chrome-extension://ggmldgjhdenlnjjjmehkomheglpmijnf/test.png">