I have fear of heights. Even a picture of a person on a dangerous height can a nasty sensation in my chest or the pains which shoot up the backs of the legs. This happened once when the picture was a black and white line drawing of a little guy on a makeshift scaffold in a cathedral under construction.
Since I knew he was merely 3/4 inch tall and made of ink, I call such fear irrational. And since Senoufou feels fear at a picture of a spider, I call that a phobia too.
Any YouTube that pops up and involves somebody falling gets the "Don't Recommend Channel" treatment from me. Ditto airplane crashes.
I have a friend who was bitten by a rattlesnake at the age of four. She needed hospitalization then, and one year later there was a resurgence of the symptoms. She will not go near any grassy or woodsy area, and she can't bear to look at a picture of any snake. Is that a phobia or not, I wonder?