Based on the definition alone I would say your friends are wrong.
art
PRONUNCIATION: ärt
NOUN: 1. Human effort to imitate, supplement, alter, or counteract the work of nature. 2a. The conscious production or arrangement of sounds, colors, forms, movements, or other elements in a manner that affects the sense of beauty, specifically the production of the beautiful in a graphic or plastic medium. b. The study of these activities. c. The product of these activities; human works of beauty considered as a group. 3. High quality of conception or execution, as found in works of beauty; aesthetic value. 4. A field or category of art, such as music, ballet, or literature. 5. A nonscientific branch of learning; one of the liberal arts. 6a. A system of principles and methods employed in the performance of a set of activities: the art of building. b. A trade or craft that applies such a system of principles and methods: the art of the lexicographer. 7a. Skill that is attained by study, practice, or observation: the art of the baker; the blacksmith's art. b. Skill arising from the exercise of intuitive faculties: Self-criticism is an art not many are qualified to practice (Joyce Carol Oates). 8a. arts Artful devices, stratagems, and tricks. b. Artful contrivance; cunning. 9. Printing Illustrative material.