diff --git a/MapControl/Shared/TileImageLoader.cs b/MapControl/Shared/TileImageLoader.cs
index 35a7ee56..fae6dd50 100644
--- a/MapControl/Shared/TileImageLoader.cs
+++ b/MapControl/Shared/TileImageLoader.cs
@@ -38,8 +38,8 @@ namespace MapControl
         public static TimeSpan DefaultCacheExpiration { get; set; } = TimeSpan.FromDays(1);
 
         /// <summary>
-        /// Format string for creating cache keys from the SourceName property and the
-        /// ZoomLevel, XIndex, and Y properties of a Tile and the image file extension.
+        /// Format string for creating cache keys from the sourceName argument passed to LoadTilesAsync,
+        /// the ZoomLevel, XIndex, and Y properties of a Tile, and the image file extension.
         /// The default value is "{0}/{1}/{2}/{3}{4}".
         /// </summary>
         public static string CacheKeyFormat { get; set; } = "{0}/{1}/{2}/{3}{4}";
@@ -50,7 +50,7 @@ namespace MapControl
 
         /// <summary>
         /// Loads all pending tiles from the tiles collection in up to MaxLoadTasks parallel Tasks.
-        /// If the UriFormat of the TileSource starts with "http" and sourceName is a non-empty string,
+        /// If tileSource.UriFormat starts with "http" and sourceName is a non-empty string,
         /// tile images will be cached in the TileImageLoader's Cache.
         /// </summary>
         public void LoadTilesAsync(IEnumerable<Tile> tiles, TileSource tileSource, string sourceName)
@@ -94,7 +94,7 @@ namespace MapControl
             Interlocked.Decrement(ref taskCount);
         }
 
-        private async Task LoadTileImageAsync(Tile tile, TileSource tileSource, string sourceName)
+        private static async Task LoadTileImageAsync(Tile tile, TileSource tileSource, string sourceName)
         {
             if (Cache != null &&
                 tileSource.UriFormat != null &&
diff --git a/MapControl/UWP/TileImageLoader.UWP.cs b/MapControl/UWP/TileImageLoader.UWP.cs
index 5f93c09d..5aaf066d 100644
--- a/MapControl/UWP/TileImageLoader.UWP.cs
+++ b/MapControl/UWP/TileImageLoader.UWP.cs
@@ -28,7 +28,7 @@ namespace MapControl
         public static Caching.IImageCache Cache { get; set; }
 
 
-        private async Task LoadCachedTileImageAsync(Tile tile, Uri uri, string cacheKey)
+        private static async Task LoadCachedTileImageAsync(Tile tile, Uri uri, string cacheKey)
         {
             var cacheItem = await Cache.GetAsync(cacheKey).ConfigureAwait(false);
             var cacheBuffer = cacheItem?.Buffer;
@@ -55,7 +55,7 @@ namespace MapControl
             }
         }
 
-        private async Task LoadTileImageAsync(Tile tile, IBuffer buffer)
+        private static async Task LoadTileImageAsync(Tile tile, IBuffer buffer)
         {
             using (var stream = new InMemoryRandomAccessStream())
             {
@@ -66,12 +66,12 @@ namespace MapControl
             }
         }
 
-        private Task LoadTileImageAsync(Tile tile, TileSource tileSource)
+        private static Task LoadTileImageAsync(Tile tile, TileSource tileSource)
         {
             return SetTileImageAsync(tile, () => tileSource.LoadImageAsync(tile.XIndex, tile.Y, tile.ZoomLevel));
         }
 
-        private async Task SetTileImageAsync(Tile tile, Func<Task<ImageSource>> loadImageFunc)
+        private static async Task SetTileImageAsync(Tile tile, Func<Task<ImageSource>> loadImageFunc)
         {
             var tcs = new TaskCompletionSource<object>();
 
diff --git a/MapControl/WPF/TileImageLoader.WPF.cs b/MapControl/WPF/TileImageLoader.WPF.cs
index 406f29f5..154cfda5 100644
--- a/MapControl/WPF/TileImageLoader.WPF.cs
+++ b/MapControl/WPF/TileImageLoader.WPF.cs
@@ -28,7 +28,7 @@ namespace MapControl
         public static ObjectCache Cache { get; set; } = MemoryCache.Default;
 
 
-        private async Task LoadCachedTileImageAsync(Tile tile, Uri uri, string cacheKey)
+        private static async Task LoadCachedTileImageAsync(Tile tile, Uri uri, string cacheKey)
         {
             ImageSource image = null;
             DateTime expiration;
@@ -64,7 +64,7 @@ namespace MapControl
             }
         }
 
-        private async Task LoadTileImageAsync(Tile tile, TileSource tileSource)
+        private static async Task LoadTileImageAsync(Tile tile, TileSource tileSource)
         {
             var image = await tileSource.LoadImageAsync(tile.XIndex, tile.Y, tile.ZoomLevel).ConfigureAwait(false);
 
@@ -74,7 +74,7 @@ namespace MapControl
             }
         }
 
-        private void SetTileImage(Tile tile, ImageSource image)
+        private static void SetTileImage(Tile tile, ImageSource image)
         {
             tile.Image.Dispatcher.InvokeAsync(() => tile.SetImage(image));
         }