Here are a few favorite pieces of movie monster/sci-fi art from the covers of a wide variety of pre-1958 magazines.
This Jan. 1934 issue of Ten Dectective Aces has an obvious swipe of Chaney's "Phantom" face. Not sure what story is being illustrated, but it's not one by Gaston Leroux.
And speaking of Lon Chaney, here's a nice portrait (sans makeup) from the June 1930 issue of Movie Monthly.
This cover of Thrilling Wonder Stories, by pulp legend Howard V. Brown, illustrates the movie version of the Henry Kuttner story. One of my favorites!
Sci-Fi Time! Destination Moon probably got more press than any other '50s sci-fi movie and the May 1950 issue of Popular Mechanics has one of the best covers.
Ziff-Davis Published a special issue of Amazing Stories with a novelization (by Henry Slesar) of Columbia Pictures' 20 Million Miles To Earth.