chromium/chrome/test/data/load_image/image_csp_img_allowed.html

<html>
<head>
  <!--
   Restrict all resource access for other origins except images. Also unblock inline script
   and eval execution for testing purposes.
 -->
  <meta http-equiv="Content-Security-Policy"
   content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; img-src * ">
</head>
<img alt="long_placeholder_text"/>
<script src="common.js"></script>
<script>
window.onload = () => {
  setTimeout(() => {
    document.images[0].src = "image.png"
  }, 1000);
}
</script>
</html>