An image processing device, comprises: a display part on which a variety of information is displayed; an image processing part for performing a plurality of image processing sequentially to process an input image data; a thumbnail image generating part for generating a thumbnail image one after the other based on the input image data or the processed image data generated sequentially in response to each image processing performed by the image processing part; an image outputting part for outputting an image based on the image data which is processed through the entire plurality of image processing; a display controlling part for displaying a processing path of the plurality of image processing performed sequentially by the image processing part from the image data is input until the image is output on the display part, and for displaying the thumbnail image along the processing path.