A piece of art can be looked at as having 3 main components, the subject, the composition and the content.
Subject
The subject of an artwork is, in simple terms, the object or objects that are depicted in the piece. For instance the subject of a piece of art could be described as a landscape, a female nude or a still life.
Composition
The composition of a piece of art is the visual arrangement of the artwork. In other words how the artist has used line, shape, colour, texture, light and shade etc. to assemble the final piece. This topic is discussed in detail in the rest of these notes.
Content
The content of an artwork is its impact or meaning, what emotional content or message the artist is attempting to communicate. Two pieces of art may have very similar subject matter, for example they could both be images of a vase of flowers as below. The way that the artist has composed the piece, ie the use of different line weights, different colours, the way light has been used and variations in shape can dramatically change the artistic content of the piece and the way that the finished piece is perceived by the audience.