Those are called 'flashbulb memories'.
[
link to en.wikipedia.org]
For example, do you remember where you were when you heard of princess Diana's death?
Shock does strange things to memory.
Quoting: Seer777 Was at home at the time and was living in Oregon Seer
Quoting: >~* Flutterby Fringe*~< I was at a friends house. Standing just outside his garage with a few others.
I don't remember where I was however, when I heard of the Challenger explosion. Seems I would remember that...
I use to often relay to others the damage one can do to ones psyche by watching some of the things available on this site or the web in general.
It is a compulsion for some reason for Man to desire to witness horror.
For example, many months ago there was a vid circulating on GLP regarding a Chinese toddler being run over, twice, then left on the road while people just passed right on by her.
I ignored the thread knowing that I should not watch said video, due to others I had seen in the past which continued to haunt me.
After much internal struggle, and seeing the thread bumped for over a week, I decided to watch it. What I saw so horrified and disgusted me, that it is burned into my memory forever.
I made a choice in that moment, to no longer expose myself to the horror which was available for me to 'click'.
And attempted to warn others from doing so.
As that once seen, can not be unseen.
Perhaps that is what Dion means by all consciousness is visual.