Main image is taken from the splash page of Showcase (DC, 1956 series) #7. Ace figure by George Tuska. Credits from Nick Caputo via the GCD Error List. Marvin Stein previously listed as inker of the main image. Per Stein's conversations with Greg Theakston, he did not ink any Challengers stories.
George Tuska drew a new splash page with the Challengers.