The upload a file function is a repository plugins. Instead of using 'Upload file' users have the option to selct files from 'Server files' and 'Private files' repositories in activities. So in principle a file could be uploaded to Moodle and compressed. The compressed file could be loaded from one of those repositories. A new repository plugin might also be made that would of compressed versions the users Private files.

Actually I think there must already be (or one time were) ways of doing the with existing repository plugins (Flickr, Picasso, Gdocs etc.).  For example users can upload a file to G Drive, manipulate it with Docs tools, and then use plugin integration to insert the content in any activity. That requires admin to set up the integration and for users to set up account with the service and then link them with Moodle. This should also work with the other office suite integration.