1. A method for converting a text sentence into an image sentence, the method comprising: receiving a text sentence comprising a plurality of words, wherein the text sentence includes a verb phrase, and wherein the text sentence is associated with a plurality of semantic roles; querying an image database, the image database having stored therein a plurality of candidate images, at least a portion of which are tagged with image content descriptors; making a determination that none of the candidate images in the image database captures each of the plurality of semantic roles associated with the text sentence; in response to making the determination, generating first and second sentence fragments from the text sentence, wherein each of the first and second sentence fragments is associated with a respective first and second fragmented semantic role; identifying a first subset of the candidate images that are stored in the image database, each of which captures the first fragmented semantic role; generating a first feature vector characterizing the first subset of candidate images stored in the image database; and identifying a first particular one of the candidate images in the first subset that is characterized by features closest to a first mean value derived from the first feature vector.