css/css-highlight-api/highlight-image.html

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <title>Custom highlight pseudo elements over images.</title>
    <link rel="help" href="https://drafts.csswg.org/css-highlight-api-1/#creating-highlights">
    <link rel="mismatch" href="highlight-image-notref.html">
    <meta name="assert" content="Highlights should be able to be specified over images.">
    <style>
    ::highlight(example-highlight1) {
        background-color: rgba(200,0,0,.5);
        color:green;
    }
    </style>
</head>
<body>
    <div id="img1"><img src="../../images/blank-highlight.png"></div>

    <script>
        let imageElement1 = document.getElementById('img1');
        let highlight1 = new Highlight(new StaticRange({startContainer: imageElement1.childNodes[0], startOffset: 0, endContainer: imageElement1.childNodes[0], endOffset: 1}));


        CSS.highlights.set("example-highlight1", highlight1);
    </script>
</body>
</html>