A shape is any area that can be perceived to have height and width. Shapes within an image can be created by the use of line, or by the edges created by variations in colour or tone. Shape can be clearly defined and easily recognisable as in the image to the left below or much more subtle and less discernable as the image on the right.
As with the use of line the way that shape is created in an image can have a large effect on the emotional content of the piece. The Image on the right above for instance, uses soft imprecise shapes which convey a dreamlike, restful state whilst the image on the left uses defined shapes which convey a sense of orderliness and that everything is in its proper place. Whenever a shape is created a negative space is also created. A negative space is the empty space around an object which the human eye will register as a shape in itself. So the negative space created by a shape is just as important to a composition as the shape itself.