README.md in radiant-event_map-extension-1.3.0 vs README.md in radiant-event_map-extension-1.3.1

@@ -59,9 +59,22 @@
 	  </body>
 	</html>
 
 Make sure that `Radiant::Config['event_map.layout']` matches exactly the _name_ of this layout.
 
+### custom markers
+
+To display a different marker for (events in) each calendar, set `Radiant::Config['event_map.use_calendar_icons?']` to true and then create shadow and marker files at paths like these:
+
+* /images/map_icons/slug.png
+* /images/map_icons/slug_shadow.png
+
+where 'slug' is the slug of each calendar. Basic pin and shadow images are included for you to modify and name appropriately.
+
+If a venue has several events then the first will event will set the marker.
+
+NB. we're not doing anything fancy here with offsets or masks: if you need that kind of detail then a bit more javascript is required.
+
 ### javascript compatibility
 
 The map javascript is generated by the EventVenuesController using `app/views/event_venues/index.js.erb`. It provides a `build_map_and_markers` method and the minimal jQuery hook required to populate #map_canvas when the DOM loads.
 
 If you're not using jQuery you should find it straightforward to call `build_map_and_markers(div element)` from another script, and in that case you don't have to use our naming scheme either.