Paintings of this style have content that closely resembles the subject matter. It does not have to have 'photographic' resemblance, although it may.
The colors should be very realistic and the lines and shapes of the subjects should be similar to how the subject would appear in real life.Realistic lighting and shadows are portrayed. Portraits are commonly done in this style as well as classic landscape paintings. Many still life paintings are painted to look 'real' although they can certainly be done in other styles.
Note that all images displayed on this page EITHER have been taken from their respective locations on wikipedia.org and are considered to be in the public domain since they are photographic reproductions of original works of art that no longer have copyrights OR are 'limited portions' of the copywritten works in order to abide by the fair use doctrine. They are being displayed here for educational purposes only. References: The Illustrated History of Art, Thinkquest Library, Paris WebMuseum and USC School of Art.