diff --git a/src/tile.js b/src/tile.js
index 582ccb67..9d29028a 100644
--- a/src/tile.js
+++ b/src/tile.js
@@ -132,7 +132,13 @@ $.Tile = function(level, x, y, bounds, exists, url, context2D, loadWithAjax, aja
      * @member {String} cacheKey
      * @memberof OpenSeadragon.Tile#
      */
+    if (cacheKey === undefined) {
+        $.console.error("Tile constructor needs 'cacheKey' variable: creation tile cache" +
+            " in Tile class is deprecated. TileSource.prototype.getTileHashKey will be used.");
+        cacheKey = $.TileSource.prototype.getTileHashKey(level, x, y, url, ajaxHeaders, postData);
+    }
     this.cacheKey = cacheKey;
+
     /**
      * Is this tile loaded?
      * @member {Boolean} loaded
diff --git a/src/tilesource.js b/src/tilesource.js
index 7a7e991c..36316a1d 100644
--- a/src/tilesource.js
+++ b/src/tilesource.js
@@ -671,21 +671,19 @@ $.TileSource.prototype = {
     },
 
     /**
-     * Most tiles are cached because their 'context2D' property is null (otherwise no caching occurs).
-     * Then, their cache is uniquely determined by this key: this key should be different if images
-     * are different! Note: default behaviour does not take into account post data.
-     *
      * A tile can have either context2D defined (TileSource.prototype.getContext2D)
-     * or it's context2D is set manually. In those cases cache is not used and this function
-     * is irrelevant.
+     * or its context2D is set manually. In those cases cache is not used and this function
+     * is irrelevant. Otherwise, the tile cache object is uniquely determined by this key:
+     * keys should be different if images are different!
+     * Note: default behaviour does not take into account post data.
      * @param level tile level it was fetched with
      * @param x x-coordinate in the pyramid level
      * @param y y-coordinate in the pyramid level
      * @param url the tile was fetched with
      * @param ajaxHeaders the tile was fetched with
-     * @param post data the tile was fetched with
+     * @param postData data the tile was fetched with
      */
-    getTileHashKey: function(level, x, y, url, ajaxHeaders, post) {
+    getTileHashKey: function(level, x, y, url, ajaxHeaders, postData) {
         if (ajaxHeaders) {
             return url + "+" + JSON.stringify(ajaxHeaders);
         } else {