update image-manager

js/image-manager.js

@@ -19,7 +19,7 @@ function ImageManager(canvasId) {
 	var canvas = canvasId;
 
 	var canvasOffsetX = canvas.offsetLeft;
-    var canvasOffsetY = canvas.offsetTop;
+	var canvasOffsetY = canvas.offsetTop;
 	
 	var context = canvas.getContext('2d');
 	var layers = new Array();