An image processing apparatus comprising: • an operation panel including: • a display means of a predetermined resolution and configured to display screens, and • an instruction means configured to allow a user to give instructions to the image processing apparatus, • processing means configured to control both functions of the image processing apparatus and display of screens on the display means, • a first storage means configured to store: • a predetermined reference resolution, • various base screen images whose sizes are adjusted at the reference resolution wherein said base screen images correspond to screens to be displayed on the display means and are composed of screen elements of various types from among any one or more button images, icon images, background images, thumbnail images, preview images, and • a reference table specifying which screens deserve and do not deserve a high quality screen image creation and its subsequent storage, wherein at least one of a warning screen, a screen including a thumbnail image, and a screen including a preview image are defined as screens not deserving the high quality screen image creation and storage, and wherein the other screens are defined as deserving the high quality screen image creation and storage, • a second storage means configured to store the created high quality screen images, wherein the processing means is further configured to, in a case it judges upon start-up that the display resolution of the display means is not equal to the stored reference resolution by comparing them to each other, and in a case it judges using the reference table upon user screen-switch instruction on the instruction means that a subsequent screen to be displayed deserves the high quality image creation and storage: • Create a first image by enlarging or reducing the base screen image to the display resolution of the display means while sacrifying image quality for speed, • Cause the display means to display the first image, • Create a high quality screen image having a higher image quality than that of the first image by enlarging or reducing the base screen image to the display resolution of the display means while sacrifying speed for image quality, • Cause the display means to display the high quality screen image as a replacement of the displayed first image, and store the created high quality screen image on the second storage means. • an operation panel including: • a display means of a predetermined resolution and configured to display screens, and • an instruction means configured to allow a user to give instructions to the image processing apparatus, • a display means of a predetermined resolution and configured to display screens, and • an instruction means configured to allow a user to give instructions to the image processing apparatus, • processing means configured to control both functions of the image processing apparatus and display of screens on the display means, • a first storage means configured to store: • a predetermined reference resolution, • various base screen images whose sizes are adjusted at the reference resolution wherein said base screen images correspond to screens to be displayed on the display means and are composed of screen elements of various types from among any one or more button images, icon images, background images, thumbnail images, preview images, and • a reference table specifying which screens deserve and do not deserve a high quality screen image creation and its subsequent storage, wherein at least one of a warning screen, a screen including a thumbnail image, and a screen including a preview image are defined as screens not deserving the high quality screen image creation and storage, and wherein the other screens are defined as deserving the high quality screen image creation and storage, • a predetermined reference resolution, • various base screen images whose sizes are adjusted at the reference resolution wherein said base screen images correspond to screens to be displayed on the display means and are composed of screen elements of various types from among any one or more button images, icon images, background images, thumbnail images, preview images, and • a reference table specifying which screens deserve and do not deserve a high quality screen image creation and its subsequent storage, wherein at least one of a warning screen, a screen including a thumbnail image, and a screen including a preview image are defined as screens not deserving the high quality screen image creation and storage, and wherein the other screens are defined as deserving the high quality screen image creation and storage, • a second storage means configured to store the created high quality screen images, • Create a first image by enlarging or reducing the base screen image to the display resolution of the display means while sacrifying image quality for speed, • Cause the display means to display the first image, • Create a high quality screen image having a higher image quality than that of the first image by enlarging or reducing the base screen image to the display resolution of the display means while sacrifying speed for image quality, • Cause the display means to display the high quality screen image as a replacement of the displayed first image, and store the created high quality screen image on the second storage means.