17. The computing device as recited in claim 16 , the accessing comprising: obtaining a specialized classifier template from a store of multiple specialized classifier templates, the obtained specialized classifier template including multiple layers; re-training a top layer of the obtained specialized classifier template using images including the particular subset of the multiple aspects; and using ones of the multiple layers below the top layer as they exist in the obtained specialized classifier template.
16. A computing device comprising: one or more processors; and a computer-readable storage device having stored thereon multiple instructions that, responsive to execution by the one or more processors, cause the one or more processors to perform acts comprising: obtaining an image stream; determining when a specialized classifier can be used to classify a particular subset of multiple aspects of content of the image stream, the specialized classifier exploiting class skew of the particular subset of the multiple aspects, the determining including identifying when the particular subset of the multiple aspects dominates the image stream; accessing the specialized classifier to classify the particular subset of the multiple aspects; and using the specialized classifier rather than a general classifier to classify the particular subset of the multiple aspects in subsequent images of the image stream.