floorplan readme updated.

images/README.md

@@ -1,5 +1,8 @@
-# Floorplan
+## Floorplan
 
-The provided floorplan is just an example which you should replace with your own.
+The provided floorplan is just an example which you should replace with your own:
 
-TODO: instructions how to replace the floorplan without producing changes in git repository (do it similar to config.js).
+![Floorplan example](floorplan-default.png "Floorplan example")
+
+Use an image editor like [paint.net](http://www.getpaint.net/index.html) to create your own individual floorplan.
+The image size is not fixed, but remember that you have to specify it (in pixels) in the module configuration.