We describe the participation of the USEMP team in the Retrieving Diverse Social Images Task of MediaEval 2015. Our runs are produced based on a supervised diversification method that jointly optimizes relevance and diversity. All runs are automated and use only resources given by the task organizers. Our best results in terms of the official ranking metric on the one-topic part of the test set came by the runs that combine visual and textual information while the textual-only run performed better on the multi-topic part.