When curators talk about the artistic vision behind a photograph, they sometimes start by explaining how the picture represents a singular moment of time and space. The artist found something special right there and then and crafted the image to capture and share that feeling.
By extension, this means that that particular moment was over by the time the film was developed or the file saved to the camera’s memory card. For the picture to represent a truly unique slice of time, everything must ultimately be ephemeral.