Original cover by Manu Larcenet; NBM 2007 (cover reprinted from Donjon Parade 3. Le Jour des Crapauds, Delcourt 2002). Anthony Vukojevich's website is here and you can purchase the original here.
Original cover attributed to Alex Kotzky; Quality Comics 1953. Michael DeForge's website is here and you can purchase a screen print of his cover here.
Original cover is by Todd McFarlane; Marvel 2004 (cover reprinted from Amazing Spider-man 316, Marvel 1989). Patrick Kochakji's website is here and his original can be purchased here.