Add ol.style.Icon#getImageSize

src/ol/style/iconstyle.js

@@ -232,6 +232,15 @@ ol.style.Icon.prototype.getImage = function(pixelRatio) {
 };
 
 
+/**
+ * Real Image size used.
+ * @return {ol.Size} Size.
+ */
+ol.style.Icon.prototype.getImageSize = function() {
+  return this.iconImage_.getSize();
+};
+
+
 /**
  * @inheritDoc
  */