An image sensor cell (100) is presented for use in an imaging device, for example of a night vision type. The image sensor cell (100) comprises an electrodes' assembly and a control unit (118). The electrodes' assembly is configured and operable to receive an input light signal and produce a corresponding electrical signal. The electrodes' assembly comprises a photocathode (112) having an active region capable of emitting electrons in response to incident light; and at least one electrode (114, 116) in a path of electrons emitted from the photocathode (112). The control unit (118) is configured and operable for controlling an electric field profile in said path so as to selectively cause the electrons' capture on said at least one electrode (114,116) resulting in accumulation of charge on said at least one electrode (114,116) corresponding to the input electromagnetic signal indicative of an acquired image, thereby enabling direct reading of the accumulated charge. The image sensor cell (100) thus provides for direct conversion of a light signal into an electric signal indicative thereof.