Imagery is visual images collectively. (117) It can be called up and terminated by an effort of will.
Imagery is the awareness of a percept that has not arisen from the sense organs but has been generated within the mind such as eidetic imagery.
Psychology is relating eidetic imagery to or denoting mental images having unusual vividness and detail, as if actually visible.
Imagery may be a result of changes of intensity and quality of perception (pareidalia).