image browsing through memory - stored items , such as a library of images or desktop windows , is efficiently performed by arranging images in partially overlapping fashion and generating a second - level image for each overlapped image that is contacted by a user - manipulated cursor . the second - level image is a “ transitory ” image , since it is removed as soon as the cursor is displaced from the corresponding first - level image . thus , by placing the first - level images in a diagonally extending stack , straight line movement of the cursor will initiate a sequential presentation of transitory images for the images in the stack . in one embodiment , the display also includes an incrementing icon and a decrementing icon that are employed to provide substitute stacks . moreover , a third - level image is formed in a separate window when the user selects one of the images from the stack . this third - level image has more permanency , since it remains in the display window after the stack has been substituted . the images may be digital photographs , but other applications are contemplated .