Iconic can only act on an image as it's requested through the image API. My understanding is that Coverart pre-renders its images outside of any user requests for that image somehow. It may be possible for Iconic to do that, too, with scheduled tasks and the like to request each image from the API so the user doesn't see it happen, but I haven't had time to look into that yet. It's probably not feasible, though, because Iconic can't act on the source image, so it would have to somehow