1. A method comprising: accessing an image that depicts an item, the item being a specimen of a product available for purchase, the product and the item having a shape represented within the image, the item depicted in the image having an attribute that describes a characteristic of the item and an attribute descriptor that corresponds to the attribute of the item and specifies a value of the attribute; identifying the attribute of the item and the attribute descriptor corresponding to the attribute 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 and identifying the shape of the item within the image based on the distinguished foreground portion of the image that depicts the item, the identifying of the attribute and the corresponding attribute descriptor being based on the identified shape of the item within the image and being performed using a processor of a machine; and storing the identified attribute descriptor as metadata of the item.