This was reported back in May 2009, and has resurfaced today.
When uploading multiple photos, the scroll bar moves to the right while the script says “creating thumbnail”. Then it eventually says “thumbnail created” and moves onto the next upload - but the thumbnail never appears.
When I search my photos, most recent date first, the non-thumbnailed images are not there. So the uploads are going into a black hole.
I have logged out and back in several times, and cleared my cache numerous times.
Not able to upload at the moment.
(note: I also tried uploading a single image and had the same result)