A term used for short term visual memory. This expression isn't particularly common in conversational usage, but is used scientifically to study memory retention of short term stimuli. The iconic memory is essentially a measurement of the ability to retain a series of elements of a visual image or stimulus, usually in alphanumeric forms, hence the 'iconic' element in the description. There were two types of test, based on 3 or 16 character sets, a whole and a partial report, focusing on retention of all or part of sets of icons.
Examples of Iconic Memory:
This is a simplified version of the standardized test:2C4N