which in turn was inspired by a European comics anthology, and I mention that comic anthology's name, which is identical with the film's name,
It's a little more complicated than that.
It started in 1974 with Métal Hurlant, a French comics magazine. (Personally, I wouldn't call it an "anthology" any more than I would call The New Yorker an anthology.)
In 1977, a licensed English-language version began publication in the USA, with the title Heavy Metal. Heavy Metal included both material originally published in Métal Hurlant and translated into English, and brand-new material by American creators.
The 1981 Heavy Metal movie, like the magazines, was a collection of short stories. Some of them were adapted from the magazine(s), and some were original.
This means that the panel in question might have its roots in the movie, or the American magazine, or the French magazine, or some combination of the three.
Métal Hurlant and Heavy Metal
It's a little more complicated than that.
It started in 1974 with Métal Hurlant, a French comics magazine. (Personally, I wouldn't call it an "anthology" any more than I would call The New Yorker an anthology.)
In 1977, a licensed English-language version began publication in the USA, with the title Heavy Metal. Heavy Metal included both material originally published in Métal Hurlant and translated into English, and brand-new material by American creators.
The 1981 Heavy Metal movie, like the magazines, was a collection of short stories. Some of them were adapted from the magazine(s), and some were original.
This means that the panel in question might have its roots in the movie, or the American magazine, or the French magazine, or some combination of the three.