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 Chinese-made giant monster snake movie about a grade school biology teacher, Lin Qi, who has written about a blood apple with miraculous healing powers that has attracted the attention of a large corporation, the Wanhong Group, which hires him to help them find it. They organize an armed expedition to go to the uninhabited island where the fruit is rumored to grow, and, of course, there is also a giant monster snake on the island. (There are also some cool flying piranha that attack in a pack and nearly kill everyone in the riverboat before the snake gets its chance. Fun fact - the name of the riverboat is Dendroaspis polylepis, which is the scientific name for the Black Mamba.)
Lin Qi wants to find the fruit to save his daughter who is dying of bone cancer. The CEO of the corporation is dying and desperately needs a cure, so he goes along with the group. The expedition also includes several armed men so there will be people for the snake to kill, a cool bad ass martial arts chick who flies through the air with knives, a young woman for a love interest for Lin Qi, and a fat guy geologist to provide some comic relief. (There's always one in these movies.)
In the beginning we see some Japanese soldiers on the mysterious island who are attacked by a gigantic snake. One of them disappeared and was found years later when he was 126 years old, which attracted the corporation's interest.
We see Lin Qi lecturing about the Titanoboa in Columbia, the largest prehistoric serpent ever found. He tells the young children in his class that they would be torn to shreds by it. Then he takes a snake from a cage and a mouse and lets the snake strike at the mouse. The children all cry and Lin Qi is thrown out of the school. (He would have been the best teacher I ever had in grade school.)
In the jungle on the island, a woman sees a snake on a tree and freaks out. One of the Rambo security guys grabs it and makes a big show of tearing off its head, ripping off some snake meat, and eating it raw. He teases everybody else, encouraging them eat some of the snake, too, but right on cue, a giant monster snake comes and swallows him. The snake tries to grab the funny guy, the martial arts chick tries to stab it in the head, a group of soldiers unsuccessfully try to shoot it before it kills them, and finally someone throws a grenade into its mouth. But it turns out that this snake isn't even the big one. There's even an interesting view from inside the giant snake's mouth which I don't think I've seen before in a movie.
So they find the fruit, etc. etc., the CEO ruthlessly kills people and takes it for himself, as if we didn't see that coming since even in Chinese movies rich powerful men are always the villain. That's because men like him aren't the audience for movies like this. If they were, they'd be the heroes, instead of the average Joes. And of course, when the monster snake finally shows up, it's goodbye time for the monster capitalist.
The monster snakes are all CGI, but we do see a couple of real live snakes, in the classroom and on the tree, both of which I think might be banded red snakes, which are common in east Asia.