L'Usage de la photo (2005) is the portrait of a unique year in Annie Ernaux's life when she was having a passionate affair as well as undergoing treatment for breast cancer. This article will explore how L'Usage de la photo, which is made up of texts and photographs by Ernaux and her partner Marc Marie, is both a representation and a proof: I shall argue that Ernaux insists on a referential link between her text and reality in this work, making it into a 'proof of life' created during the period of her illness. Using the figure of metamorphosis to describe the relationship that Ernaux posits between her text and its eventual reception, I show how its structure helps her, almost as much as her partner does, to survive her ordeal. As her condition improves, Ernaux inclines towards disowning both project and partner in her reignited desire for life and normality. The competing drives in the work between chronicling her illness and rejecting it in the first flush of health are ultimately resolved in an image: an untaken, imaginary photograph symbolizing maternity. I argue that this final portrait shows Ernaux giving birth to the book, her lover, and her post-cancerous self.