I’m dealing with a lot of open KML and GeoJSON files, and some times people have specified URLs (especially in now unmaintained files) for Billboard icons that no longer exists. Is there some way to get an event or some other means of tracking these as they fail? (We have automated systems that can override, overwrite or alert users on what to do, etc.) None of the datasource events fires.
There’s a 7 year old open issue on Git for the same; Better error handling for billboard if image cannot be loaded · Issue #3117 · CesiumGS/cesium · GitHub