in one's mind's eye
In one's imagination or memory. For example, I can just see the old farm in my mind's eye. This term pairs mind and eye in the sense of “a mental view.” [Early 1400s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.