diff --git a/lib/OpenLayers/Layer/WMS/Untiled.js b/lib/OpenLayers/Layer/WMS/Untiled.js
index 23e1cea2fd..056cd3254a 100644
--- a/lib/OpenLayers/Layer/WMS/Untiled.js
+++ b/lib/OpenLayers/Layer/WMS/Untiled.js
@@ -150,6 +150,11 @@ OpenLayers.Layer.WMS.Untiled.prototype =
             var ul = new OpenLayers.LonLat(tileBounds.left, tileBounds.top);
             var pos = this.map.getLayerPxFromLonLat(ul);
 
+            if ( this.tile && !this.tile.size.equals(tileSize)) {
+                this.tile.destroy();
+                this.tile = null;
+            }
+
             if (!this.tile) {
                 this.tile = new OpenLayers.Tile.Image(this, pos, tileBounds, 
                                                      url, tileSize);