สอบถามการใส่รูปภาพ marker google map อยากจะ custom marker ครับ

//Base Color
var base_color = '#9dc500';

//Google Maps Coordinates
var google_maps_latitude = 16.8234;
var google_maps_longitude = 100.262;


function startGmap() {
	
	var myOptions = {
		zoom: 16,
		center: new google.maps.LatLng(google_maps_latitude, google_maps_longitude),
		navigationControlOptions: {style: google.maps.NavigationControlStyle.ZOOM_PAN, position: google.maps.ControlPosition.RIGHT_TOP},
		streetViewControl: false,
		scrollwheel: false,
		zoomControl: true,
		zoomControlOptions: {
      		style: google.maps.ZoomControlStyle.LARGE,
      		position: google.maps.ControlPosition.RIGHT_TOP
    	},
		mapTypeControl: false,
		mapTypeControlOptions: {
			style: google.maps.MapTypeControlStyle.DROPDOWN_MENU,
      		position: google.maps.ControlPosition.TOP_RIGHT,
			mapTypeIds: ["ptMap"]
		}
	};
	
	map = new google.maps.Map(document.getElementById('contact_map'), myOptions);
	
	var styleCP = [
		{ featureType: "administrative", elementType: "all", stylers: [ { visibility: "off" } ] },
		{ featureType: 'landscape', elementType: 'all', stylers: [ { hue: '#3bffoo' }, { saturation:20 }, { lightness:50 }, { visibility: 'on' } ] },
		{ featureType: "poi", elementType: "all", stylers: [ { visibility: "off" } ] },
		{ featureType: "road", elementType: "all", stylers: [ { visibility: "on" }, { lightness:0 } ] },
		{ featureType: "transit", elementType: "all", stylers: [ { visibility: "off" } ] },
		{ featureType: "water", elementType: "all", stylers: [ { saturation: 20 }, { lightness: 50 } ] },
		{ featureType: "all", elementType: "all", stylers: [ { saturation: 20 }, { lightness: 50 } ] }
	];
		
	var styledMapOptions = {name: "Map"};
  	var ptMapType = new google.maps.StyledMapType(styleCP, styledMapOptions);
  	map.mapTypes.set("ptMap", ptMapType);
  	map.setMapTypeId("ptMap");  
	
	/**/
	
	var circle = {
  		path: google.maps.SymbolPath.CIRCLE,
	    fillOpacity: 0.75,
	    fillColor: base_color,
	    strokeOpacity: 1.0,
	    strokeColor: base_color,
	    strokeWeight: 1.0, 
	    scale: 20
	};
	
	var point = new google.maps.LatLng(google_maps_latitude, google_maps_longitude);
	
	var marker = new google.maps.Marker({
		position: point,
		map: map,
		zIndex: 99999,
		optimized: false,
		icon: circle
	});
	
}