Add image loading events to image sources

src/ol/source/imagemapguidesource.js

@@ -1,5 +1,7 @@
 goog.provide('ol.source.ImageMapGuide');
 
+goog.require('goog.events');
+goog.require('goog.events.EventType');
 goog.require('goog.object');
 goog.require('goog.uri.utils');
 goog.require('ol.Image');
@@ -15,6 +17,7 @@ goog.require('ol.source.Image');
  * Source for images from Mapguide servers
  *
  * @constructor
+ * @fires ol.source.ImageEvent
  * @extends {ol.source.Image}
  * @param {olx.source.ImageMapGuideOptions} options Options.
  * @api stable
@@ -150,6 +153,8 @@ ol.source.ImageMapGuide.prototype.getImage =
     image = new ol.Image(extent, resolution, pixelRatio,
         this.getAttributions(), imageUrl, this.crossOrigin_,
         this.imageLoadFunction_);
+    goog.events.listen(image, goog.events.EventType.CHANGE,
+        this.handleImageChange, false, this);
   } else {
     image = null;
   }