In general, the subject matter described in this specification can be embodied in methods, systems, and program products. A computing system accesses an indication of a first template that includes a region of a first image. The region of the first image includes a graphical representation of a face. The computing system receives a second image. The computing system identifies indications of multiple candidate templates. Each respective candidate template from the multiple candidate templates includes a respective candidate region of the second image. The computing system compares at least the first template to each of the multiple candidate templates, to identify a matching template from among the multiple candidate templates that includes a candidate region that matches the region of the first image that includes the graphical representation of the face.