At the dawn of the age of psychedelia, the cover for Rubber Soul by The Beatles shows how powerful a light touch can be.
The slightly distorted cover image is trippy without being totally cosmic - reflecting the gradual shift towards studio experimentation that can be heard in the music contained within. The portrait was taken by photographer Bob Freeman and the stretched version was born when the card that Freeman was projecting potential cover shots onto slipped, creating an effect that was an immediate hit with the band.
Bonus trivia: Rubber Soul was the first Beatles album not to feature the band's name on the cover. Although this wasn't a pop first, it was certainly uncommon in 1965.