A display device, a screen display method, and an image processing apparatus are provided. When a resolution of a display portion is different from a reference resolution, manufacturing of high-definition images of a reference image formed by a screen made of a size matching the reference resolution and storage of the manufactured images in a storage unit are performed only in a necessary condition, and a risk that saved images having high use possibility are deleted mechanically from the storage unit is lowered; when the resolution of the display portion is not consistent with the reference resolution, a first image which is manufactured at a high speed in a speed priority manner is displayed during initial screen display. After a high-definition second image is manufactured, the second image is switched and displayed, and the second image is displayed while the storage unit has the second image during screen migration. Judgment if a screen is a screen deserving or not deserving storing the second image in the storage unit or not is performed according to the judgment reference which is preset according to the screen, and the second image is manufactured and stored when the screen is the screen deserving storage.