CesiumJS not displaying globe with image - cesiumjs

Question

I'm trying to display a heatmap over the globe in Cesium but the globe isn't even showing up on the screen, only the background is. I looked in the network part of google chrome and it shows the actual image I need being loaded from the server.
<script>
var count=0;
var viewer = new Cesium.CesiumWidget('cesiumContainer');
var layers = viewer.scene.imageryLayers;
var imageArray = <?php echo json_encode($images) ?>// PARSING PHP ARRAY INTO JAVASCIPT
alert(imageArray[0]);
var date;var name='HeatMap-2006-01-16.png'; //FOR INITAL PAGE LOAD
loadCesium();
function loadCesium()
{
//Cesium Active Window
layers.addImageryProvider(new Cesium.SingleTileImageryProvider({
url : 'images/'.concat(name),
rectangle : Cesium.Rectangle.fromDegrees(-180.0, -90.0, 180.0, 90.0)
}));
}
function overlayChange()
{
name = imageArray[count];
for (i = 0; i < name.length; i++)
{
if(name.charAt(i)=="-")
{
date = name.substring(i);
break;
}
}
loadCesium();
count = count + 1;
}
function overlayChangeBack()
{
if(count == 0)
{
count = 39;
name = 'HeatMap';
name = name.concat(count.toString());
loadCesium();
}
else
{
name = 'HeatMap';
count=count-1;
name = name.concat(count.toString());
loadCesium();
}
}
</script>
Right now I'm just trying to display the name variable('HeatMap-2006-01-16.png') for the initial image but it's not displaying. No image I try to put instead displays either so it's definitely an issue with cesium.

Answer 1

I'm not sure why this fixed it because I've had it working without this statement but when declaring the cesiumContainer in the variable viewer, you have to set it as this:
var viewer = new Cesium.CesiumWidget('cesiumContainer', {
imageryProvider : new Cesium.ArcGisMapServerImageryProvider({
url : 'http://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer'
}),
baseLayerPicker : false
});