I have to add my $0.02 worth to this:
All plugins deactivated (just to be 100% sure)
Everything else works out of the box as advertised.
These are the symptoms:
Sometimes the upload dialog reappears after the upload, other times clicking "Upload" causes the whole dialog (page section) to disappear. Meaning: that section of the write posts page is blank. Neither image type or image size seems to have an effect that can be documented.
Sometimes uploading an image succeeds, except the thumbnail option/radio button above "send to editor" fails to appear. Now I can duplicate (on the occasions the entire upload area is visible, that is) the problem, and it does seem to be related to image size. So I hacked around and eliminated php memory limitations, plus the megapixel limit - however the problem still exists.
Several other people on different servers also running 2.3 have reported the exact same symptoms to me. I'm on a dedicated box, but can also reproduce these symptoms on a virtual host. My colleagues are on virtual hosting boxes.
On my dedicated and virtual boxes I've adjusted permissions on wp-content/uploads to something far more liberal than I'm comfortable with, and ownership is per the httpd.conf, meaning that the web server can read and write to the directories it needs to.
Is there a workaround for either of the issues above? Is there a plugin that can assume this functionality? A search has so far revealed nothing meaningful.
WordPress gurus; we could use some guidance as to why this is happening.
Regards & TIA,