As more and more traditional publishers accept digital images, artists are turning to free and open source software (FOSS) tools to create cartoons and illustrations.
Both vector and bitmap drawing programs let you draw lines. Generally speaking, vector lines are more reusable and revisable, while bitmap lines are more artistic.
Before starting a drawing in any tool, plan how many layers your drawing will have. A simple bitmap drawing may have only three or four layers, such as a background, a character, and a car. A vector drawing may have more layers; even a single property in your drawing may have several layers. Using layers can make it easier for you to revise your drawing or reuse it in another drawing in the future.