diff --git a/changelog/upgrade-notes.md b/changelog/upgrade-notes.md
index d473ef0b5b..247368e163 100644
--- a/changelog/upgrade-notes.md
+++ b/changelog/upgrade-notes.md
@@ -118,7 +118,7 @@ size of a sub-rectangle in an image sprite.
 
 ### Support for non-square tiles
 
-When using ´ol.tilegrid.TileGrid#getTileSize` on the tile grid of an `ol.source.BingMaps`, the return value will now be an `ol.Size` array instead of a number.
+The return value of ´ol.tilegrid.TileGrid#getTileSize()` will now be an `ol.Size` array instead of a number if non-square tiles (i.e. an `ol.Size` array instead of a number as `tilsSize`) are used. To always get an `ol.Size`, the new `ol.size.toSize()` was added.
 
 ### v3.4.0
 
diff --git a/src/ol/source/bingmapssource.js b/src/ol/source/bingmapssource.js
index 406102c437..f1eb3f415d 100644
--- a/src/ol/source/bingmapssource.js
+++ b/src/ol/source/bingmapssource.js
@@ -107,7 +107,8 @@ ol.source.BingMaps.prototype.handleImageryMetadataResponse =
     extent: ol.tilegrid.extentFromProjection(sourceProjection),
     minZoom: resource.zoomMin,
     maxZoom: maxZoom,
-    tileSize: [resource.imageWidth, resource.imageHeight]
+    tileSize: resource.imageWidth == resource.imageHeight ?
+        resource.imageWidth : [resource.imageWidth, resource.imageHeight]
   });
   this.tileGrid = tileGrid;