Pics can't be uploaded to Media Library

Updated from 3.5 to 3.5.1. yesterday (installed on my own webspace).

Now I’m no longer able to upload images. When I try it seems to upload, than the page went white. When I go back to the Media Library I can see the picture. But when I click on it to edit it says, that it’s not properly uploaded and I should try again.

I tried emptying the browser cache. Tried to use different browsers. Deactivated all plugins and went back to the wordpress theme.

Nothing seems to help. Anything else I can do?