FIXME

imgio

The function names below are not particularly consistent.  We are
aiming for supporting _binary, _gray, _rgb, and _packed versions where
appropriate.  The _rgb version should return a w x h x 3 array, while
the _packed version should return a w x h array with 24bit packed
color results.  We will also consistently support bytearray and
floatarray for the binary/gray/rgb versions, and intarray for the
packed versions.  And we need to consistently support using both file
names and stdio streams for input/output.