A high-key image consists primarily of light tones, without dark shadows. A photograph or painting so composed features a diminished tonal range of primarily whites and light grays. High key as a term used in describing paintings or photographs is related to but not the same as high-key lighting in cinema or photography. ...
A light image that is intentionally lacking in shadow detail
Exclusive use of pale or light values within a given area or surface.
A light image that is intentionally lacking in shadow detail. 
Term describing a photograph which contains large areas of light tones, with few mid-tones or shadows. (see: Low key)
a style of lighting that is bright, even, and produces little contrast between light and dark areas of the scene.