Welcome to APF, aykattack. I don't know much about Spanish-language photos like 6 of the lobby card-like pics that you have posted, but I believe the 13x20 print of the poster itself is a repro. I don't think they were printing 13x20s of any movie posters in 1981, the original year of this film's release. Especially in the Spanish-language campaigns...
Here is a current, one sheet-sized poster for sale on ebay...
http://cgi.ebay.com/Jules-Verne-Mystery-Monster-Island-FRANK-FRAZETTA-OS-/250456752385?pt=LH_DefaultDomain_0&hash=item3a5062c101If the small version of this poster is printed on the same type paper as all of the photos that you bought and are the exact same size, I suspect they might all be repros. Did you buy all of these from the same seller? Did you buy them on Ebay, or somewhere else?
There also appears to be two different styles of the lobby card and another piece that looks like a contact sheet of numerous pics. It is an odd assortment.
Maybe one of our members will have a more definitive answer.
BTW, despite what the art looks like and the ebay seller's description that I posted, Frank Frazetta did not provide the art. They are just swipes from at least three of Frazetta's more famous pieces.