I am using Max 6.1.6, 64 bit version, on a Mac with OS X 10.9.1. Although it is stated that there is limited support for video functionality using 64 bit Max, I have not seen any reports that image files will be loaded incorrectly if they are saved at less than or equal to 72 DPI.
I noticed the problem when certain images loaded by jit.qt.movie and jit.matrix appeared completely skewed to the point of being unrecognizable. After ruling out various possibilities, I found that if you open the jit.qt.movie help file and load this image --
-- it displays properly. That image is 76 DPI. However, if you load this image --
-- it displays improperly. That image is 70 DPI, but otherwise is identical in content, format, and compression settings.
I wanted to let anyone who might also have this problem know here so you can be spared some debugging time. I do not know if this problem happens on a Windows machine or with early OS X versions.
If I am mistaken, please let me know! It will spare me a lot of headache if there is some simple cause for this I have overlooked.