dream vs mental picture

dream

verb
  • To hope, to wish. 

  • To see imaginary events in one's mind while sleeping. 

  • To envision as an imaginary experience (usually when asleep). 

  • To consider the possibility (of). 

  • To daydream. 

adj
  • Ideal; perfect. 

noun
  • Imaginary events seen in the mind while sleeping. 

  • A visionary scheme; a wild conceit; an idle fancy. 

  • A hope or wish. 

mental picture

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