All photographs are memento mori. To take a photograph is to participate in another person’s (or thing’s) mortality, vulnerability, mutability. Precisely by slicing out this moment and freezing it, all photographs testify to time’s relentless melt.

– Susan Sontag in On Photography, quoted in Alexis Madrigal’s Dance as Algorithm: What Happens When an Animated GIF Springs to Life via Kevin Slavin.