diff --git a/includes/script.js b/includes/script.js
index 70814a1..b301238 100644
--- a/includes/script.js
+++ b/includes/script.js
@@ -123,6 +123,13 @@ $(document).ready(function() {
         // get tiles
         bitsyData.tiles = {};
 
+        // tile 0 (background colour only) is implicit in bitsy rather than being stored in the game data
+        // so, make our own version
+        bitsyData.tiles[0] = {
+            name: 0, 
+            bitmap: _.chunk(_.split(_.repeat(0, 64), ''), 8)
+        };
+
         var tiles = input.match(/TIL (.*)\n([01]{8}\n){8}/g);
 
         if (tiles.length > 0) {   
diff --git a/readme.md b/readme.md
index c25fad5..ab88e8a 100644
--- a/readme.md
+++ b/readme.md
@@ -40,15 +40,13 @@ if (src.match(/^(file|https)?:\/\/|^\/\//)) {
 
 ## known bugs
 
-* tile 0 (background colour only) is an implicit tile in Bitsy- it's not stored in the game data. so this tool ignores it. oops!!
-    * when importing game data, create a version of this
-    * when writing game data, don't write the 0 tile
 
 ## to do
 
 * allow user to save output as image, or tweet it :) *user can currently right-click -> Save As but the 128x128 size is not great*
 * create new tiles based on image
     * only add unique new tiles
+    * don't write the 0 tile (implicit background-only tile)
 * implement slider (*always use existing tiles* -> *always create new tiles*) (representing 0-64 threshold for # of common pixels)
 * re-style the damn thing
 * reorganise the page layout for a more logical workflow