Thumbnail sketches are quick, abbreviated drawings, usually done very rapidly and with no corrections. You can use any medium, though pen or pencil is the most common. Thumbnail sketches usually are very small, often only an inch or two high.

What is a thumbnail sketch and what is it's purpose?

A thumbnail sketch is a small quick drawing that can help you to plan out a, larger painting or drawing. They are especially useful for understanding the main light and dark values in your composition. A thumbnail drawing is only about 2 – 3 inches in size, which makes it easy to be able to simplify.

What is the synonym of fanciful?

Some common synonyms of fanciful are chimerical, fantastic, imaginary, quixotic, and visionary. While all these words mean "unreal or unbelievable," fanciful suggests the free play of the imagination.