collage vs photomosaic

collage

noun
  • A picture made by sticking other pictures onto a surface. 

  • A composite object or collection (abstract or concrete) created by the assemblage of various media; especially for a work of art such as text, film, etc. 

  • The technique of producing a work of art of this kind. 

verb
  • To make into a collage. 

photomosaic

noun
  • A composite image made of individual photographs, normally of the same shape and size, placed together - to show a panoramic view etc. 

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