On my iPad 3 and iPhone 4S, I cannot reproduce the trouble you describe. We'll keep investigating your problem report.
If Revel has completed uploading al photos you have imported, your photos are safely stored in the Revel cloud and it is OK to uninstall and reinstall the app. In the Revel app, do you see "Up-to-date," or a cloud icon that shows syncing is still happening? If you are unsure, sign into your account via a desktop browser at www.adoberevel.com and confirm your original photos can be downloaded.
If you are unsure about any of this, to be absolutely safe, be sure your iPad's photos are safely backed up outside of Revel before uninstalling and reinstalling the app.