I never noticed any snakes in the Frazetta art that I saw. Obviously, it was there. Mostly what i saw was found in the Edgar Rice Burroughs books. So, if it was in that, it escaped my attention. But I never have liked snakes and I'm not very interested in seeing snakes in art, either. I disagree with Justice Potter Stewart, though, when he said he knew porn when he saw it. i think something like that can vary too much from one person to another to really define porn in that manner. Certainly, I don't think the Whitesnake album cover is pornographic. To me it fits in with what they were doing. I agree with the comments Coverdale made about the matter.
Chris Achilleos may not have made the polished art that Frank Frazetta came out with, but it seems he did what was needed at the time. I never even saw that album cover when it came out. Was it banned in the U.S.? I wouldn't be surprised. But at that time I had a job that required me to travel so much it would have been easy to miss something like that. I've got the CD ordered now, though.
After having said these things about sci-f/fantasy art, it is no surprise that I'll also admit "Heavy Metal" is one of my favorite movies even to this day. I had no idea Chris Achilleos drew that poster for the movie. This makes me like him even more.