We investigate the impact of the background luminance upon the perceived image quality of real world scenes. To do so, we generate a set of small image patches that span the full range of mean luminance values and contrasts that may be displayed upon a monitor with a finite luminance range. Subjects viewed the images on a uniform black, grey or white surround and were asked to rate the perceived quality on a scale from 0 to 9. We find that that the maximum image quality scores occur for images with a mean luminance of less than half, consistent with the image being passed through a compressive non-linearity before contrast is computed. Moreover, the maximum image quality scores occur at lower mean luminance levels when the background luminance is darker, a pattern consistent with investigations into lightness perception. We conclude that models of contrast perception require an adaptive model of lightness perception. However, we also note the considerable challenge of developing a model of lightness perception that can generalize to any given display configuration.