Concept art
Real world article
(written from a production point of view)
Concept art for the Galaxy-class Enterprise-D by Andrew Probert
Concept art is a form of traditional or digital illustration, allowing the art department to offer directors, producers, or other production personnel rough options to choose from before developing a final design. Concepts can depict props, make-up, wardrobe, sets, ships, or special effects.
Numerous reference works, magazines, and bonus features have offered a look behind the scenes at the concept art that's gone into making Star Trek.
See also: Category:Memory Alpha images (concept art)