The great getImageData/putImageData conundrum
=============================================

Current API:
                              |  Present     |  Future
 -----------------------------+--------------+---------------
  Author does the right thing | it all works | it all works
 -----------------------------+--------------+---------------
  Author assumes low-res data | it all works | data cropped
 -----------------------------+--------------+---------------

  Summary:
    50% change that pages will work well in future versions.
    50% change that pages will fail badly in future versions.



An API that provides both low-res and high-res (1:1) data:
                                        |  Present     |  Future
 ---------------------------------------+--------------+---------------
  Author uses high res correctly        | it all works | it all works
 ---------------------------------------+--------------+---------------
  Author uses high res, assumes low res | it all works | data cropped
 ---------------------------------------+--------------+---------------
  Author uses low res correctly         | it all works | data ugly
 ---------------------------------------+--------------+---------------

  Summary:
    33% change that pages will work well in future versions.
    67% change that pages will be usable in future versions.
    33% change that pages will fail badly in future versions.
    API is more complicated and has an essentially useless feature.


Executive summary: We're screwed either way, but the more complicated
API basically trades complexity for increasing the odds of pages
working at all in future versions by 17%.