mid-14c., "to form a mental image of," from Old French imaginer "sculpt, carve, paint; decorate, embellish" (13c.), from Latin imaginari "to form a mental picture, picture to oneself, imagine" (also, in Late Latin imaginare "to form an image of, represent"), from imago "an image, a likeness," from stem of imitari "to copy, imitate" (from PIE root *aim- "to copy"). Sense of "suppose, assume" is first recorded late 14c. Related: Imagined; imagining.
Proto-Indo-European root meaning "to copy."
It is the hypothetical source of/evidence for its existence is provided by: Latin imago "image," aemulus "emulous," imitari "to copy, portray, imitate;" Hittite himma- "imitation, substitute."
early 15c., "portray, paint, form a likeness of in color," from Latin depictus, past participle of depingere "to portray, paint, sketch; describe, imagine," from de "down" (see de-) + pingere "to paint" (see paint (v.)). Extended sense of "portray in words, describe" is from mid-15c. Related: Depicted; depicting.