         #   a color table
         Object.defineProperty this, 'overlays',
           get: ->
-            @volume.session.overlays
+            @volume.container.session.overlays
       
       # Transfers the file content to the data properties.
       # The image state loading flag is set to true while the
       # files are being read.
       #
-      # @returns a promise which resolves when the file reads
-      #   are completed
+      # @returns a promise which resolves to this image object
+      #   when the file is loaded 
       load: ->
         # Set the loading flag.
         @state = Image.STATES.LOADING

      # @param image the selected PK modeling parameter name, or 'none' to 
      #  remove an existing overlay
      deselectOverlay: ->
         @xtkVolume.labelmap.visible = false if @xtkVolume.labelmap?

      # Changes the overlay label map and color lookup table as follows:
      # * Fetch the overlay files.

          @xtkVolume.filedata = data
          # Set the state to loaded.
          @state = Image.STATES.LOADED
          # Return the loaded image.
          this

      isLoaded: ->
        @state == Image.STATES.LOADED

      isLoading: ->
        @state == Image.STATES.LOADING
      
      # Renders the image in the given parent element.
      #
      # @param element the Angular jQueryLite element
