12. The system of claim 11 , the operations further comprising: for each query term, obtaining a weight for the query term by applying the vector of image feature values to a respective image relevance vector for the query term, wherein each component of the image relevance vector indicates a relative importance of each corresponding component in the vector of image feature values in determining whether the query term is relevant, wherein selecting the subset of the query terms is based on the respective weight for each query term.
12. The system of claim 11 , the operations further comprising: for each query term, obtaining a weight for the query term by applying the vector of image feature values to a respective image relevance vector for the query term, wherein each component of the image relevance vector indicates a relative importance of each corresponding component in the vector of image feature values in determining whether the query term is relevant, wherein selecting the subset of the query terms is based on the respective weight for each query term. 13. The system of claim 12 , the operations further comprising mapping the vector of image feature values to one or more query term and weight pairs.