Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This is a jungle adventure about a rich artist who travels to the jungle with an expedition searching for a radioactive waterfall that makes the locals glow in the dark and makes anyone else spontaneously combust.
In the first scene of the movie we see a man take a snake out of a cage and put it on the ground near an artist who is painting a woman posing sitting on the ground. The woman sees the snake and screams "A snake! Someone help! Don't move!" then we see the man who released the snakes kill the snake by bashing its head in with a pole. The artist tells him he should check the area better next time.
We learn later that the artist is named Valdemar, the woman is his wife Linda, and the man who released the snakes is the jungle guide they hired named Chuck. Chuck was trying to kill Valdemar because he is having an affair with Linda and they want to run away together.
The snake is a non-venomous constrictor of some kind, maybe a python or a boa constrictor, that would pose no threat to any human. Even if a snake is dangerously venomous, it's absurd to think that you could just put it near someone and it would crawl over and bite them like some kind of heat-seeking missile. But unfortunately, this happens all the time in movies. In the real world, the snake would most likely crawl away to somewhere it could hide.