Having the same issue… seems to be rather pervasive with 2.9.2. My testing so far has included:
1) Tested uploading with Firefox, IE 8, and Chrome
2) Tested uploading with and without Google Gears
3) Tested uploading after resetting Misc settings (upload path, etc)
4) Tested uploading with both the flash and browser upload dialog
5) Tested uploading after setting all wp-content perms to 777
6) Tested uploading after re-upgrading to 2.9.2
Always with the same result… I get the status bar for uploading, then crunching, then nothing. When I check with an FTP client the file is present, but no thumbnails were generated, nor does it appear in the Media Library.
Needless to say this is a pain.
UPDATE: Just set up a completely virgin 2.9.2 install and the upload worked. Arrrgh! Will now have to piece together my production site again using a virgin install, i.e. not an upgrade. Maybe that’s the key.