An image sensor cell includes a first MOS transistor coupled to an operating voltage for providing an output voltage of the image sensor cell with the output voltage changing conformingly with a voltage on a gate of the first MOS transistor. A photodiode is coupled to a floating node which further controls the voltage of the gate of the first MOS transistor. A photoconductor is coupled between the operating voltage and the floating node. The photoconductor has its resistance varying in response to a magnitude change of an imposed illumination so that the floating node is provided with additional electrical charges conformingly through the photoconductor while the photodiode drains electrical charges, thereby decreasing a voltage reduction rate of the voltage on the gate of the first MOS transistor.