icon vs spitting image

icon

noun
  • A small picture that represents something. 

  • A person or thing that is the best example of a certain profession or some doing. 

  • An image, symbol, picture, or other representation usually as an object of religious devotion. 

  • A type of religious painting portraying a saint or scene from Scripture, often done on wooden panels. 

  • A word, character, or sign whose form reflects and is determined by the referent; onomatopoeic words are necessarily all icons. 

spitting image

noun
  • The exact likeness (of someone). 

How often have the words icon and spitting image occurred in a corpus of books? (source: Google Ngram Viewer )