The essay film is defined by its capability to embody an audiovisual thinking process. Chris Marker’s Sans soleil/Sunless (1983) is undoubtedly one of the highest expressions of this filmic form, which reflects on postmodernity through the nature of images. This article aims to analyse the thinking in act of the film, using Jacques Rancière's concept of sentence-image, and applying Gilles Deleuze's theory of the time-image and the crystal-image. The cinematic thinking process thus develops through a succession of sentence-images, which forces the spectator to constantly transform the actual image/virtual image relationship of the film until it reaches a time-image and crystal-image of postmodernity. It is possible thanks to the shifts among the different subjectivities created by Marker and the interstices they generate. This shift also reaches a crystal-image as a materialisation of the postmodern concept of alterity as analysed by Paul Ricœur and Zygmunt Bauman. The reflection is constructed by means of an itinerary through four types of images and their screens –film image, television image, electronic image and video game image– in order to develop the image-memory-history axis and to generate an audiovisual reflection on postmodernity in total consonance with Jean Baudrillard's theory of the image, Marc Augé's of non-places or Fredric Jameson's of the postmodern historicism.