Culinary art is essentially a technique of cooking and preparing food which is not only appealing from a perspective of taste, but also from a visual one. Therefore, culinary art involves as much of an understanding of aesthetics, as it does of cooking.
It is for this reason that culinarians or those considered experts in culinary art usually have a formal educational background in the field, in most cases from a culinary school. That is where they also learn aspects such as nutrition or diet control. In the process, they also imbibe various hospitality etiquette which may or may not have anything to do with food at all. For instance, the ways in which customers are greeted or the ways in which orders are either taken or served, are all aspects that are taught at culinary school.
Garnishing or the way food is decorated is one of the major aspects of culinary art. In case you recall those chain mails and email forwards that had fruits and vegetables cut in unique shapes such as flowers or movie characters, then what you were looking at was essentially garnishing, done from a perspective of high-end culinary art.
In this context, it would be vital to mention that culinary art is not the forte of only the high flying restaurants or hotels such as five stars; a lot of the simpler eating joints, including fast food joints also indulge in culinary art. For instance, when you order fried chicken at KFC and it comes in a standard shape and form, irrespective of the location of the outlet at which you are ordering, that is also an aspect of culinary art.