The artist knows what he used, we do not.
But Photoshop offers plenty of tools to make it without setting every pixel separately. Curves can be drawn maybe a little easier in Illustrator, but one can paste them to Photoshop. Textures can be imported as images and the snake can originally be a well crafted photo or a rendered 3D sculpt. High quality stuff can be purchased - I guess layout artists do not have time for such highly detailed tinkering to get a single object.
Here's a tiny sample of Photoshop's possibilities to insert much details with little effort. Let's have a shape drawn with the Pen (sorry for it's puny look, the artist has been 1000% more accurate with his curves):
It's colored and layer style Bevel&Emboss is inserted. Now it resembles metal:
Nobody guarantees the artist has used tricks this simple. A capable painter could insert lights and shadows manually.
Why I have not published as fine works? Should it be in contradiction with the fact that I have now and hundreds of times before this claimed I know a way to draw something?
No contradiction. Simply I'm not able to imagine anything as fine.