Sometimes, or several, you can find comic book covers from another country, similar with ones from the US market. Why is this? My take is... At least in México, and since the beginnings of the hobby, our artists had great collections of american comic books, that being because they were fans, or because they tried to use the material as reference or as teaching tools.
Problems arose when, due to laziness ( which is more common than you would think) or impending deadlines, which ocurred because the artist in question took more work than humanly possible ( payment for this kind of job always have been cheap) or last, but not least, artist's blockade, they resorted to tracing covers from their collection! Even with spots or dirt smears! Anyway, sometimes, they got less than perfect pieces; but editors never were too demanding...
For example, this is the original, Dr. Strange from 1974:
And this this the traced product, from 1986!
Incredible how they got away with this, didn't they? copyright laws never have been strict around here, so...
There have been MANY, many examples of this "borrowing" of ideas. But they weren't constricted to only comic books. There were taken from any and all all graphic work available.
There is this one, where the artist took a very famous photograph by Bunny Yeager of Betty Page, a really famous pin-up artist from the fifties, and traced it to make a cover of Santo, El Enmascarado de Plata # 151, from 1963!
We could put many more examples, to no end, but I expect this serves well to describe a tendency that pervades even to this day. And I'll try to show more examples in the near future
Thanks for looking at and reading my posts!