In an image processing apparatus adapted to apply user-settable image processing to a sensed image, real time display in an electronic viewfinder of an image to which a user-set image processing is applied and an image to which such image processing is not applied is switched with each passage of a predetermined period of time or in response to a user operation. Implementing a preview function with the electronic viewfinder image enables the user to check the results of the image processing in real time prior to actual image sensing by comparing the processed image and the original image to provide an easy-to-use preview function.