I have come to the conclusion that Posterous is missing something in the image headers. This image was rotated correctly when I looked at it before I sent it, and Flickr got the rotation right when autoposted via Posterous. Time to file a bug.
Because it's christmas, you get extra frequent Emma pictures!
(And it's really too bad that once a post is up on posterous, you can't fix the image rotation. I tried to fix it on my phone, but somehow once it got to the internets, it went back to sideways)
This picture has been sitting on my camera for about a month now, and I finally copied it off.