1. An electronic device, comprising: a display; control circuitry that generates image frames that are displayed on the display; and a charge accumulation tracker that evaluates the image frames to identify when a risk of excessive charge accumulation in the display is present, wherein the charge accumulation tracker computes a median gray level for all pixels in a given one of the image frames and computes a charge accumulation metric for the given one of the image frames based on inputs including the median gray level, and wherein the charge accumulation tracker applies a weighting function to the median gray level when computing the charge accumulation metric.