Here is my scenario:
- I choose many files - all of them are named P39283982.jpg
- I upload them (not seeing thumbnails).
- I release all rights.
- OMG! I just remembered I cannot upload this one! Where is the back button!
At a very least the user should be able to remove the file or cancel the whole process. Currently you are left alone and don't even know where the files are and how to remove them.