1. A method performed by a data processing apparatus, the method comprising: receiving, in response to a search query for resources received from a user device, a set of search query suggestions, each search query suggestion being based on the search query and different from the search query; for each search query suggestion, receiving data identifying a respective set of images determined to be responsive to the search query suggestion; for each respective set of images, generating a representative image set depicting a subset of the respective set of images determined to be responsive to the search query suggestion; for a particular source of images: determining a first number of images determined to be responsive to the search query that are hosted by the particular source and that are in a set of top ranked images responsive to the search query, wherein the set of top ranked images has a second number of images greater than the first number of images, and the second number of images includes the images that are hosted by the particular source and images hosted by other sources; determining that the particular source of images determined to be responsive to one or more query suggestions has a diversity measure that meets a diversity threshold, where the diversity measure is a measure of the first number of images to the second number of images, and in response: generating a representative image set that depicts a subset of images hosted by the particular source; providing to the user device, in response the search query, a search results page resource, the search results page resource including instructions that cause the user device to render a search results page that includes: a set of search results that identify images that are determined to be responsive to the search query; for each search query suggestion, generating a search query suggestion grouping including: data describing the search query suggestion; data depicting the representative image set; and a selectable link associated with the search query suggestion grouping; generating data depicting the representative image set that depicts the subset of images hosted by the particular source and an associated selectable link.