1. A machine-readable medium having no transitory signals and storing instructions which, when executed by at least one processor of a machine, cause the machine to perform operations comprising: receiving a selection of an image, the image being a search result from a plurality of search results obtained based on a matching process performed on a current search string; determining a keyword corresponding to the selected image; appending the keyword corresponding to the selected image to the current search string; refining the plurality of search results based on the appending of the keyword; and causing presentation of the refined search results.