I have a WordPress installation, where any files that are uploaded by the user via the media library are set to the permission level 600 on the server by default. This results in the file not being accessible after upload. Images will not be displayed for instance. And uploaded files cannot be downloaded.

What can I do to change the default file permission for uploaded files to something, so that the file can be accessed via the browser? (What permission level does it need and how can I make it default for any uploaded file?)