1. A method comprising: receiving data specifying a first image; receiving text labels for the first image; for each of one or more of the text labels: receiving search results in response to a web search performed using the text label as a query, each search result referencing a web resource; assigning a text label ranking score to the text label based on a number of the resources referenced by the received search results that include an image matching the first image; ranking the text labels, at least in part, based on the text label ranking scores assigned to text labels; and selecting an image label for the first image from the ranked text labels, the image label being selected based on the ranking.