1. A computer-implemented method comprising: receiving, at a computing device comprising a processor, a test image and a plurality of object images detected to depict an object similar to the test image, the object comprising a plurality of attributes; identifying a plurality of attribute values of the object depicted in the object images, the attribute values being stored in a metadata associated with each object image; and for each attribute, estimating a corresponding attribute value of the object depicted in the test image based on the attribute values stored in the metadata associated with the object images.