Ralph Waldo Emerson, an American thinker, a poet, and an essayist, said "The Quality of the Imagination is to flow and not to freeze."
Imagination is an ability to be able to draw what you saw in your heart, and it is a basic of your spiritual activity. It is a tool to exceed time and place within your mind.
Columbus imagined the earth to be round and sailed to the ocean and made great discovery. Einstein also imagined a world where everything is relative and developed the theory of relativity.
The way imagination works is different among everyone but it does work.