How our brain works is that It takes in information, process the information through brain and stores the information processed in our brain. When any information is fed to the brain, we process the information like asking how, why, when, and then not only the information itself is stored but the whole processed information is stored. So storing the whole processed information helps us retrieve the real information itself because no information is information itself as it has been the outcome of our understanding. When we see the face, our mind process the information about the face like its structure of nose, eyes, mouth, whole face and the relative distance between each of the facial element. So what gets stored in the memory is not directly the image of the face but the complete understanding of the face about its positioning and the structure. In the same way we process any image, text, etc. so the important part of memorizing is processing the information that is understanding. We store the whole information and the relation of the information with the each other (by our logic) which is the blue print. So how we retrieve information. Whenever we are asked a question, we look in the memory of the similar knowledge, then you retrieve the logic and the whole information. The whole point is that logic makes the storing and retrieval of information to and from the memory. We remember what seems logical to us. Just put logic to anything or pictures because pictures have lots of logic. An image is thousands of words. So to store a little information, the whole chunk of logical information should be stored. We store more information that we understand. Logic creates association of information.