Last week I upgraded to 2.5.1 and applied the .htaccess hack to make the flash image uploader work correctly - which it did. I come to use it today and it now behaves oddly.
I go through the upload process as normal and the upload appears to be working fine until after 'crunching'. At that point I see a blank image and blank fields where the title etc. would be. So no errors given. I don't even try to insert as there's nothing there.
The blank image also shows up in the media gallery and there is a reference to it in the database as an attachment (as there should be), but with no URL. Looking in wp-content/uploads/(date folder) I don't see the image and can't find one elsewhere in the file system.
So to me it appears the image isn't uploaded at all, but somehow the uploader thinks it is. What's really weird is how this worked fine the other day and nothing has changed either in my WP settings or on the server.