Using images as markers on map legend

HTML

<script src="https://www.amcharts.com/lib/3/ammap.js"></script>
<script src="https://www.amcharts.com/lib/3/maps/js/worldLow.js"></script>
<div id="chartdiv"></div>

CSS

#chartdiv {
    width : 100%;
    height : 500px;
}

JavaScript

AmCharts.makeChart("chartdiv", {

    "type": "map",
        "dataProvider": {
        "map": "worldLow",
            "getAreasFromMap": true
    },
        "areasSettings": {
        "autoZoom": true,
            "selectedColor": "#CC0000"
    },
        "legend": {
            "backgroundColor": "#fff",
            "backgroundAlpha": 0.7,
            "align": "center",
        "data": [{
            title: "One",
            color: "#3366CC",
            customMarker: ""
        }, {
            title: "Two",
            color: "#FFCC33",
            customMarker: "http://www.amcharts.com/lib/3/images/motorcycle.png"
        }]
    }
});