We report on the fabrication of a 2-D array (16 x 16) of optical thyristors connected into a winner-takes-all network with capability of spatially resolved maximum optical dose detection. In every pixel of the network, optical energy is integrated in time (during up to 1 ms) by means of precharging of the optoelectronic thyristors. At the moment of verdict, a voltage step is applied to the whole 256 element array. Only the element with the highest stored charge then switches on and holds off all other thyristors. A differential resolution of 80 pJ optical energy has been measured, while the time to take the appropriate decision is less than 150 ns.