11. A classification system comprising: a general classifier configured to classify multiple aspects of content of an image stream; a template store including multiple different specialized classifier templates, each of the specialized classifier templates being configured to classify a subset of the multiple aspects; and a classifier selection system configured to re-train one of the multiple different specialized classifier templates to generate a specialized classifier for a particular subset of the multiple aspects, and to determine when to switch between using the general classifier to classify the multiple aspects of content of the image stream and using the specialized classifier to classify the multiple aspects of content of the image stream.
14. The classification system as recited in claim 11 , the general classifier comprising a first deep neural network, and the specialized classifier comprising a second deep neural network that is shallower than the first deep neural network.