There is no other way than what I have stated. That is why the upgrade documentation states to take a backup of your mysql database before doing the upgrade. You always need a restore point if something does wrong. If you do not have a backup of the photos table there is no way to get them back besides reuploading every last one.
Now you can contact your host and see if they have a backup of the database. It might be a day or two old or week old but its better than nothing.