Hello.
I just upgrade my wordpress to 3.3 a few hours ago, and I have a similar problem.
When I upload an image, all works well, there is no script errors too, but the image doesn’t appear.
I checked the directory with my ftp-client and the image appears in the site!, but it has size of 0kb. I tried to change the permissions (but they already had to 777).
Thanks for the help.