I think we should, in a world of cloud computing and remote data storages, start to discuss on how to make phpBB handle different upload providers.
The idea is like this:
- provide an abstraction over file uploads in phpBB
- provide a default provider - plupload
- enable extensions to add custom providers (Amazon S3, Dropbox, Azure, ...)
- phpBB would only be a mediator between enduser and the provider - it would take a file from the user and forward it to the provider
- provider class would be responsible for permanent file storage and permanent accessibility of the file, giving phpBB only unique identification of the image (that would be used to link file to post/avatar)