diff --git a/MapControl/MapImage.Silverlight.WinRT.cs b/MapControl/MapImage.Silverlight.WinRT.cs
index 6cd66b48..2a9b6885 100644
--- a/MapControl/MapImage.Silverlight.WinRT.cs
+++ b/MapControl/MapImage.Silverlight.WinRT.cs
@@ -12,13 +12,13 @@ namespace MapControl
 {
     public partial class MapImage
     {
-        private static readonly Transform imageTransform = new MatrixTransform
-        {
-            Matrix = new Matrix(1d, 0d, 0d, -1d, 0d, 1d)
-        };
-
         private void SourceChanged(ImageSource image)
         {
+            var imageTransform = new MatrixTransform
+            {
+                Matrix = new Matrix(1d, 0d, 0d, -1d, 0d, 1d)
+            };
+
             Fill = new ImageBrush
             {
                 ImageSource = image,
diff --git a/MapControl/MapImage.WPF.cs b/MapControl/MapImage.WPF.cs
index 3c3b7e75..3be1e5cf 100644
--- a/MapControl/MapImage.WPF.cs
+++ b/MapControl/MapImage.WPF.cs
@@ -2,7 +2,6 @@
 // Copyright © Clemens Fischer 2012-2013
 // Licensed under the Microsoft Public License (Ms-PL)
 
-using System.Windows;
 using System.Windows.Media;
 using System.Windows.Media.Imaging;
 
@@ -10,19 +9,22 @@ namespace MapControl
 {
     public partial class MapImage
     {
-        private static readonly Transform imageTransform = new ScaleTransform(1d, -1d);
-
         private void SourceChanged(ImageSource image)
         {
             var bitmap = image as BitmapSource;
 
             if (bitmap != null)
             {
-                image = new TransformedBitmap(bitmap, imageTransform);
+                var imageTransform = new ScaleTransform(1d, -1d);
+                imageTransform.Freeze();
+
+                bitmap = new TransformedBitmap(bitmap, imageTransform);
+                bitmap.Freeze();
+
+                image = bitmap;
             }
 
             Fill = new ImageBrush { ImageSource = image };
-            SetBrushTransform();
         }
     }
 }
\ No newline at end of file
diff --git a/MapControl/MapRectangle.WPF.cs b/MapControl/MapRectangle.WPF.cs
index 0c5c0679..c5f08281 100644
--- a/MapControl/MapRectangle.WPF.cs
+++ b/MapControl/MapRectangle.WPF.cs
@@ -13,20 +13,9 @@ namespace MapControl
         {
             StrokeThicknessProperty.OverrideMetadata(
                 typeof(MapRectangle), new FrameworkPropertyMetadata(0d));
-        }
 
-        protected void SetBrushTransform()
-        {
-            var tileBrush = Fill as TileBrush;
-
-            if (tileBrush != null && Data != null)
-            {
-                var geometry = (RectangleGeometry)Data;
-
-                tileBrush.ViewportUnits = BrushMappingMode.Absolute;
-                tileBrush.Viewport = geometry.Rect;
-                tileBrush.Transform = geometry.Transform;
-            }
+            FillProperty.OverrideMetadata(
+                typeof(MapRectangle), new FrameworkPropertyMetadata(FillPropertyChanged));
         }
 
         private void SetGeometry(Rect rect)
@@ -40,7 +29,8 @@ namespace MapControl
 
             geometry.Rect = rect;
             geometry.Transform = ParentMap.ViewportTransform;
-            SetBrushTransform();
+
+            SetBrushTransform(Fill as TileBrush);
         }
 
         private void ClearGeometry()
@@ -50,5 +40,25 @@ namespace MapControl
             geometry.ClearValue(RectangleGeometry.RectProperty);
             geometry.ClearValue(Geometry.TransformProperty);
         }
+
+        private void SetBrushTransform(TileBrush tileBrush)
+        {
+            if (tileBrush != null && Data != null)
+            {
+                var geometry = (RectangleGeometry)Data;
+
+                tileBrush.ViewportUnits = BrushMappingMode.Absolute;
+                tileBrush.Viewport = geometry.Rect;
+                tileBrush.Transform = geometry.Transform;
+            }
+        }
+
+        private static void FillPropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
+        {
+            if (e.NewValue != e.OldValue)
+            {
+                ((MapRectangle)o).SetBrushTransform(e.NewValue as TileBrush);
+            }
+        }
     }
 }