Add custom icons with Markers | Mapbox GL JS

Use Marker to add custom icons to your map.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Add custom icons with Markers</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no">
<link href="https://api.mapbox.com/mapbox-gl-js/v2.2.0/mapbox-gl.css" rel="stylesheet">
<script src="https://api.mapbox.com/mapbox-gl-js/v2.2.0/mapbox-gl.js"></script>
<style>
body { margin: 0; padding: 0; }
#map { position: absolute; top: 0; bottom: 0; width: 100%; }
</style>
</head>
<body>
<style>
.marker {
display: block;
border: none;
border-radius: 50%;
cursor: pointer;
padding: 0;
}
</style>
 
<div id="map"></div>
 
<script>
	// TO MAKE THE MAP APPEAR YOU MUST
	// ADD YOUR ACCESS TOKEN FROM
	// https://account.mapbox.com
	mapboxgl.accessToken = '<your access token here>';
var geojson = {
'type': 'FeatureCollection',
'features': [
{
'type': 'Feature',
'properties': {
'message': 'Foo',
'iconSize': [60, 60]
},
'geometry': {
'type': 'Point',
'coordinates': [-66.324462890625, -16.024695711685304]
}
},
{
'type': 'Feature',
'properties': {
'message': 'Bar',
'iconSize': [50, 50]
},
'geometry': {
'type': 'Point',
'coordinates': [-61.2158203125, -15.97189158092897]
}
},
{
'type': 'Feature',
'properties': {
'message': 'Baz',
'iconSize': [40, 40]
},
'geometry': {
'type': 'Point',
'coordinates': [-63.29223632812499, -18.28151823530889]
}
}
]
};
 
var map = new mapboxgl.Map({
container: 'map',
style: 'mapbox://styles/mapbox/streets-v11',
center: [-65.017, -16.457],
zoom: 5
});
 
// add markers to map
geojson.features.forEach(function (marker) {
// create a DOM element for the marker
var el = document.createElement('div');
el.className = 'marker';
el.style.backgroundImage =
'url(https://placekitten.com/g/' +
marker.properties.iconSize.join('/') +
'/)';
el.style.width = marker.properties.iconSize[0] + 'px';
el.style.height = marker.properties.iconSize[1] + 'px';
el.style.backgroundSize = '100%';
 
el.addEventListener('click', function () {
window.alert(marker.properties.message);
});
 
// add marker to map
new mapboxgl.Marker(el)
.setLngLat(marker.geometry.coordinates)
.addTo(map);
});
</script>
 
</body>
</html>