We need more robust feedback when uploading a Photo

(Bug, Investigate , Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Photos
Summary: Kate has observed that it's very hard to know how the upload is going, and whether it has failed. She's right -- the feedback so far is still pretty weak.
This needs design, but we should probably unify photo-upload with the mechanisms in, eg, Import.
The visual design for this feedback isn't obvious. The linear progress bar might not be right, given the space. Maybe put the percentage in the middle of the spinner, and some text below it?
If at all possible, we should show more-robust feedback for the actual percentage-uploaded. Sadly, the JS-level tool hasn't given us much help there; we might enhance the existing Import feedback mechanism to reflect that better?