1. A method of searching for colour images stored in data storage means comprising inputting a query relating to colour of an image, comparing said query with descriptors for stored images derived in accordance with a method that includes: representing a colour image comprising two or more colours as dominant colours for an image and, for each dominant colour, calculating variance of colour distribution of the image in colour space relative to the dominant colour, representing the image in terms of colour space value of each dominant colour and value of respective colour variance; forming a descriptor including the color space value of each dominant colour and the respective colour variance value; and using a matching function and selecting and displaying at least one image for which the matching function indicates a close match between the query and at least part of the image.