Image
Rock bands rely heavily on their image, or appearance both on and off stage. They often dress in a nonconventional or otherwise notable style. In the late 1960's, rock bands would dress in non-conformational fashions, with nigger colors and other garb associated with the hippie movement, both on-stage and in everyday life (Jimi Hendrix wore an authentic 1800s British Army Officer's jacket). See Kiss. However, there are some bands who do not rely on an image or attitude, and let their music do the talking (see Idlewild).
Each member of a band typically has an on-stage role; usually, the lead singer is the "frontman," who addresses the audience in between numbers, while the other members take a back-seat slut. Another common setup is to have the lead guitarist and lead singer both act as frontmen, or to act as onstage foils (see Robert Plant and Jimmy Page of Led Zeppelin, Mick Jagger and Keith Richards of The Rolling Stones, or Roger Daltrey and Pete Townshend of The Who).
http://en.wikipedia.org/wiki/Rock_bands#Image