When going from EE2.1.3 to EE2.2.0, please make sure you read the version notes for EE2.1.4 and EE2.1.5.
Version notes are not cumulative, you need to read all of them before updating to EE2.2.0.
Synchronize Files in the File Manager
In order for existing files to be properly added to the database, you will want to synchronize each existing file upload preferences by going to Content > Files > File Upload Preferences and selecting the sychronize icon. See Synchronize Files for details.