Images for Gmaps pins - RoR

Question

I have a gallery of images that correspond to pins on a map. I would like to have the pins be a small 32x32 thumbnails of those gallery images.

In my controller:

def index
  @arts = Art.all

  @hash = Gmaps4rails.build_markers(@arts) do |art, marker|
  marker.lat art.latitude
  marker.lng art.longitude
  marker.infowindow art.artist
  marker.picture({
    url: :mural,
    width: 32,
    height: 32,
  })
end

you can see I tried to call :mural where you would normally have a URL to a single image. This just shows blank.

I've also tried w/ a variation that I call to get the images in the gallery Art.mural.url(:thumb) with no luck.

My map script in my index:

<div>
 <script type="text/javascript">
  handler = Gmaps.build('Google');
  handler.buildMap({ provider: {}, internal: {id: 'map'}}, function(){
    markers = handler.addMarkers(<%=raw @hash.to_json %>);
    handler.bounds.extendWith(markers);
    handler.fitMapToBounds();
    handler.getMap().setZoom(15);
  });
 </script>

using the Gmaps4Rails gem

Answer 1

Posted as answer since it solves the problem.

Do:

art.mural.url(:thumb)

To pass a valid url