An image processing system can realize a more accurate and high-quality correction of defective pixels by including an image pickup device, an obtaining unit obtaining information showing positions of defective pixels occurred at the image pickup device, a creating unit creating discrimination information showing the positions of the defective pixels in an image generated via the image pickup device, a detecting unit detecting a correlativity with neighborhood pixels by each defective pixel, and an estimating unit estimating a pixel value by each defective pixel in accordance with a detected result by the detecting unit. Incidentally, the image processing system is configured by an imaging device and a computer recording an image processing program, in which the imaging device includes the image pickup device, the obtaining unit, and the creating unit, and the image processing program may make the computer function as the detecting unit and the estimating unit.