That's an interesting issue and IMO a bug.
The content_types_registry is mainly meant to handle filetype to contenttype conversion when uploading via WebDAV. When doing a file upload via the folder_contents I would expect to have an image OR a file created - and not the file converted to a content type.
@pfraterdeus - can you please file a bug report at https://github.com/plone/Products.CMFPlone/issues and mention me (I'm @thet on github)
@gp54321 there is a ui for managing these entries: just add "/content_type_registry/manage_predicates" to the URL at the root of your Plone site, e.g. http://localhost:8080/Plone/content_type_registry/manage_predicates . It's from the ZMI, the Zope Management Interface.