A method includes deriving a plurality of semantic categories for
representing important semantic cues in images, where each semantic
category is modeled through a combination of perceptual features that
define the semantics of that category and that discriminate that category
from other categories; for each semantic category, forming a set of the
perceptual features comprising required features and frequently occurring
features; comparing an image to said semantic categories; and classifying
said image as belonging to one of said semantic categories if all of the
required features and at least one of the frequently occurring features
for that semantic category are present in said image. A database contains
image information, where the image information includes at least one of
already classified images, network locations of already classified images
and documents containing already classified images. The database is
searched for images matching an input query, including, e.g., an image,
text, or both.