Graphics vs Text : Picture superiority effect

According to the picture superiority effect, concepts are much more likely to be remembered experientially if they are presented as pictures rather than as words.According to dual-coding theory by Allan Paivio (1971, 1986), memory exists either (or both) verbally or “imaginally”. Concrete concepts presented as pictures are encoded into both systems; however, abstract concepts are recorded only verbally.

http://en.wikipedia.org/wiki/Picture_superiority_effect