1. A method comprising: accessing an image that depicts an item, the item being a specimen of a product available for purchase, the item having an attribute that describes a characteristic of the item and a descriptor that specifies a value valid for the attribute, identifying the attribute of the item and the descriptor of the item based on an analysis of the image, the analysis including distinguishing a foreground portion of the image that depicts the item from a background portion of the image from which the item is absent, the identifying of the attribute and the descriptor being performed using a processor of a machine; and storing the identified descriptor of the item as metadata of the item.