1. A method of processing a digital image, comprising the steps of: a) assigning belief values according to instructions stored in a computer readable medium to pixels in the digital image, the belief values are subject to: (i) detecting a probability of both human skin color pixels and non-skin color pixels in the digital image and (ii) computing a geometric feature for spatially contiguous regions of skin-colored pixels, wherein the belief values are proportional to a belief that the skin color and non-skin color pixels are associated with human skin; b) ascertaining an image dependant adaptive skin probability threshold using both the human skin color pixels and the non-skin color pixels having desired gradient values; c) calculating a brightness adjustment amount based on a statistic of the pixels with belief values exceeding the skin probability threshold and the assigned belief values of the pixels; and d) applying the brightness adjustment amount to the digital image to produce a processed digital image having improved overall brightness.