Esri/esri-leaflet — pull request #195 by johnwebbcole (2014-01-14 22:11:20+00:00)
Title: When removing a DynamicMapLayer that is outside the min/max zoom levels,...

A simple fix for a DynamicMapLayer that hasn't drawn an image due to the map zoom level. When using a layer control and you uncheck the layer, it will throw an error because _currentImage is null.