18. The computer-program product of claim 15 , further comprising instructions configured to cause a data processing apparatus to: display previews of the plurality of files, wherein the previews of the plurality of files are arranged in an overlapping manner, and wherein using the displayed previews of the plurality of files includes moving backwards or forwards through the displayed previews.
18. The computer-program product of claim 15 , further comprising instructions configured to cause a data processing apparatus to: display previews of the plurality of files, wherein the previews of the plurality of files are arranged in an overlapping manner, and wherein using the displayed previews of the plurality of files includes moving backwards or forwards through the displayed previews. 19. The computer-program product of claim 18 , wherein selecting a particular preview of a particular file in the plurality of files causes the particular preview of the particular file to become a focal point among the displayed previews.