An illustration is a visualization such as a drawing, painting, photograph or other work of art that stresses subject more than form. The aim of an illustration is to elucidate or decorate textual information (such as a story, poem or newspaper article) by providing a visual representation.

Illustrations can:

* give faces to characters in a story;
* display examples of an item described in an academic textbook (e.g. a typology);
* visualize step-wise sets of instructions in a technical manual;
* communicate subtle thematic tone in a narrative;
* link brands to the ideas of human expression, individuality and creativity; and
* inspire the viewer to feel emotion to expand on the linguistic aspects of the narrative.

Illustrators confronted a challenge from those using computer software such as Adobe Illustrator, Photoshop, and CorelDRAW. The use of Wacom tablets and similar apparatus also increased the ability of drawing and painting directly in a computer.

Today, many illustration students are made aware of the technology available, with equal emphasis placed upon more traditional illustration techniques. As a result, traditional and digital techniques are often used in conjunction with each other.

While illustrations have been previously been considered just a small part of the creative and entertainment industries, they are becoming a new and significant factor in industries such as video games, movies, animation, advertising and publishing, the former three known for their use of concept art in pre-production.

An illustrator is a graphic artist who specializes in enhancing writing by providing a visual representation that corresponds to the content of the associated text. The illustration may be intended to clarify complicated concepts or objects that are difficult to describe textually, or the illustration may be intended for entertainment, as in greeting cards, or cover art or interior art for books and magazines, or for advertisement, as on posters.

Most contemporary illustrators make their living creating artwork for use in children's books, advertising, newspapers and magazines. Pen and ink and airbrush artists traditionally dominated this realm.

Computers dramatically changed the industry, and today computers are used to produce most of the commercial illustrations.

However, traditional illustration techniques are still popular, particularly in the field of book illustration. Watercolor, oil painting, pastels, wood-engraving, linoleum cuts, and pen and ink are some of the traditional techniques used by successful exponents of the art.

There are no formal qualifications needed to become an illustrator. However, many established illustrators attended an art school or college of some sort and were trained in different painting and drawing techniques. Art Colleges and Universities now offer specific courses in illustration.

Many illustrators are freelance, commissioned by publishers (of newspapers, books or magazines) or advertising agencies. Most of the scientific illustrations and technical illustrations are also known as information graphics. Among the information graphics specialists are medical illustrators who illustrate human anatomy, often requiring many years of artistic and medical training.