Print information comes to us either via an image or in text. Images have been made for thousands of years to convey information to those who had access to sacred caves & rocks.
The ALPHABET historically speaking is a more recent invention, dating back about 5000 years.
Read this I Love Topography for a detailed history of the alphabet.
When you read this excellent research link pay particular attention to how this incredible communication technology was formed. From a visual reality representation of the thing as an PICTURE to a visual symbolic representation of it as a CONCEPTUAL IMAGE to a symbolic sound representation by a letter that would form part of a written word that finally came to represent the thing.
We use different parts of our brain to decode information. Images are decoded holistically which is to say your brain takes in the whole image at once what we call the GESTALT. Where as a word is usually placed in a linear stream of other words and so is decoded sequentially, scanned one word at a time , the whole meaning is derived at the end of a sentence. If you read the whole sentence you will get the meaning, but an Image explodes in your face fully formed.
ALL PLANETS ARE ROUND. THE EARTH IS A PLANET. THE EARTH IS ROUND.
Without seeing the image of the Earth you would read the 3 short sentences and get the meaning and some kind of image would form in your mind, but as soon as you look at the image of the Earth you get meaning straight away.
WRITING and its decoding activity READING is LEFT BRAIN function. VIEWing images is a RIGHT BRAIN function. An excellent resource on this topic is