An image processing device includes a switch signal generator, an amplifier, a ramp generator, and an attenuation control circuit. The switch signal generator generates switch control signals based on a level of an image signal that corresponds to a pixel signal output from a pixel. The amplifier includes a first input terminal and a second input terminal. The ramp generator generates a ramp signal. The attenuation control circuit adjusts an arrangement of capacitors according to the switch control signals to control whether to attenuate each of the pixel signal and the ramp signal, and transmits signals generated as a result of the adjusted arrangement to the first input terminal and the second input terminal.