Title: Can You Spot Dark Energy in a Map With 100 Million Pixels? Abstract: The apparent photographic shape of a distant galaxy is typically slightly stretched by so--called weak gravitational lensing: the slight bending of light due to the gravitational field of the inhomogeneously distributed foreground mass. Several large astronomical surveys have either been proposed or are underway to measure this effect statistically, over a large fraction of the sky. The properties of the lensing distortion depend on the nature of the mass-energy distribution in the universe. Indeed, weak lensing is currently believed to be one of the most promising approaches to solving the mystery of dark energy, the dominant contribution to the present-day mass-energy. I will describe recent analytical methods and numerical simulations, which attempt to quantify how well we can constrain the properties of dark enery with large maps of the lensing distortion. I will also argue that our existing forecasts have not fully clarified the information content of such maps, and will attempt to provoke computer scientists (and others) to come up with a better statistical approach.